I added and then removed a newline from my file.
clicked build all
This caused a save which messed up the file and caused several exceptions to be thrown.  The first was in a dialog and the second was in the terminal.

#########################################################################
System.InvalidOperationException: Tried to remove non ws chars: ' {
                if (description_entry.Sensitive == false) {
                                description_entry.Sensi
                }ti                 true;

				string desc = Item.Current.D                iption;
				if (description_entry.Text                    esc) {
					description_entry.Text = desc == null ? String.Em                : desc;
				}
                          else {
				description_entry.Sensiti                 false;
				description_entry.Text = St            g.E            y;
			}

			description_entry.Changed += HandleDescriptionChanged;               }

		'
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.AddChange (Int32 offset, Int32 removedChars, System.String insertedText) [0x001a7] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:756 
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.FixEmbeddedStatment (BraceStyle braceStyle, BraceForcement braceForcement, MonoDevelop.CSharp.Dom.CSharpTokenNode token, Boolean allowInLine, MonoDevelop.CSharp.Dom.DomNode node) [0x001bb] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:607 
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.VisitIfElseStatement (MonoDevelop.CSharp.Dom.IfElseStatement ifElseStatement, System.Object data) [0x00060] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:833 
  at MonoDevelop.CSharp.Dom.IfElseStatement.AcceptVisitor[Object,Object] (MonoDevelop.CSharp.Dom.DomVisitor`2 visitor, System.Object data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/Statements/IfElseStatement.cs:72 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitChildren (MonoDevelop.CSharp.Dom.DomNode node, MonoDevelop.CSharp.Dom.T data) [0x0000c] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:37 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitBlockStatement (MonoDevelop.CSharp.Dom.BlockStatement blockStatement, MonoDevelop.CSharp.Dom.T data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:178 
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.VisitMethodDeclaration (MonoDevelop.CSharp.Dom.MethodDeclaration methodDeclaration, System.Object data) [0x00061] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:452 
  at MonoDevelop.CSharp.Dom.MethodDeclaration.AcceptVisitor[Object,Object] (MonoDevelop.CSharp.Dom.DomVisitor`2 visitor, System.Object data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/TypeMembers/MethodDeclaration.cs:74 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitTypeDeclaration (MonoDevelop.CSharp.Dom.TypeDeclaration typeDeclaration, MonoDevelop.CSharp.Dom.T data) [0x0001a] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:91 
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.VisitTypeDeclaration (MonoDevelop.CSharp.Dom.TypeDeclaration typeDeclaration, System.Object data) [0x000e8] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:196 
  at MonoDevelop.CSharp.Dom.TypeDeclaration.AcceptVisitor[Object,Object] (MonoDevelop.CSharp.Dom.DomVisitor`2 visitor, System.Object data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/GeneralScope/TypeDeclaration.cs:92 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitChildren (MonoDevelop.CSharp.Dom.DomNode node, MonoDevelop.CSharp.Dom.T data) [0x0000c] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:37 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitNamespaceDeclaration (MonoDevelop.CSharp.Dom.NamespaceDeclaration namespaceDeclaration, MonoDevelop.CSharp.Dom.T data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:85 
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.VisitNamespaceDeclaration (MonoDevelop.CSharp.Dom.NamespaceDeclaration namespaceDeclaration, System.Object data) [0x00068] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:160 
  at MonoDevelop.CSharp.Dom.NamespaceDeclaration.AcceptVisitor[Object,Object] (MonoDevelop.CSharp.Dom.DomVisitor`2 visitor, System.Object data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/GeneralScope/NamespaceDeclaration.cs:87 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitChildren (MonoDevelop.CSharp.Dom.DomNode node, MonoDevelop.CSharp.Dom.T data) [0x0000c] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:37 
  at MonoDevelop.CSharp.Dom.DomVisitor`2[T,S].VisitCompilationUnit (MonoDevelop.CSharp.Dom.CompilationUnit unit, MonoDevelop.CSharp.Dom.T data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/DomVisitor.cs:45 
  at MonoDevelop.CSharp.Formatting.DomIndentationVisitor.VisitCompilationUnit (MonoDevelop.CSharp.Dom.CompilationUnit unit, System.Object data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/DomIndentationVisitor.cs:85 
  at MonoDevelop.CSharp.Dom.CompilationUnit.AcceptVisitor[Object,Object] (MonoDevelop.CSharp.Dom.DomVisitor`2 visitor, System.Object data) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Dom/CompilationUnit.cs:97 
  at MonoDevelop.CSharp.Formatting.CSharpFormatter.OnTheFlyFormat (MonoDevelop.Projects.Policies.PolicyContainer policyParent, System.Object textEditorData, Int32 startOffset, Int32 endOffset) [0x0007b] in /mnt/data/code/monodevelop/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Formatting/CSharpFormatter.cs:110 
  at MonoDevelop.Projects.Text.Formatter.OnTheFlyFormat (MonoDevelop.Projects.Policies.PolicyContainer policyParent, System.Object textEditorData, Int32 startOffset, Int32 endOffset) [0x00026] in /mnt/data/code/monodevelop/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.Text/Formatter.cs:95 
  at MonoDevelop.SourceEditor.SourceEditorView.Save (System.String fileName, System.String encoding) [0x000f3] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/SourceEditorView.cs:371 
  at MonoDevelop.SourceEditor.SourceEditorView.Save (System.String fileName) [0x00000] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/SourceEditorView.cs:342 
  at MonoDevelop.Ide.Gui.Document.Save () [0x00123] in /mnt/data/code/monodevelop/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.Gui/Document.cs:241 
  at MonoDevelop.Ide.ProjectOperations.DoBeforeCompileAction () [0x00112] in /mnt/data/code/monodevelop/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide/ProjectOperations.cs:1054 
  at MonoDevelop.Ide.ProjectOperations.Build (IBuildTarget entry) [0x0007f] in /mnt/data/code/monodevelop/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide/ProjectOperations.cs:989



#########################################################################
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208 
Exception in animation:System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-managed) object:ElementAddr (object,int,int,int,int,int)
  at MonoDevelop.SourceEditor.MessageBubbleHighlightPopupWindow.RenderInitialPixbuf (Gdk.Window parentwindow, Rectangle bounds) [0x0001c] in /mnt/data/code/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/MonoDevelop.SourceEditor/MessageBubbleHighlightPopupWindow.cs:62 
  at Mono.TextEditor.Theatrics.BounceFadePopupWindow.OnExposeEvent (Gdk.EventExpose evnt) [0x00060] in /mnt/data/code/monodevelop/main/src/core/Mono.Texteditor/Mono.TextEditor.Theatrics/BounceFadePopupWindow.cs:208

<snip>Lots of errors about unexpected symbol 'X'