Diff editor does not work anymore

System.NullReferenceException: Object reference not set to an instance of an object
  at Mono.TextEditor.TextArea.RenderMargins (Cairo.Context cr, Cairo.Context textViewCr, Cairo.Rectangle cairoRectangle) [0x00139] in /Users/builder/data/lanes/432/49c110a8/source/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/Mono.TextEditor/Gui/TextArea.cs:1972 
  at Mono.TextEditor.TextArea.ExposeEventInternal (Gdk.EventExpose e) [0x000b9] in /Users/builder/data/lanes/432/49c110a8/source/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/Mono.TextEditor/Gui/TextArea.cs:2057 
  at Mono.TextEditor.TextArea.OnExposeEvent (Gdk.EventExpose e) [0x0000b] in /Users/builder/data/lanes/432/49c110a8/source/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/Mono.TextEditor/Gui/TextArea.cs:2034

ERROR [2018-03-14 11:55:21Z]: An unhandled exception has occured. Terminating Visual Studio? False
  System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object
    at Mono.TextEditor.TextArea.VAdjustmentValueChanged () [0x000be] in /Users/alan/Projects/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/Mono.TextEditor/Gui/TextArea.cs:249 
    at Mono.TextEditor.TextArea.VAdjustmentValueChanged (System.Object sender, System.EventArgs args) [0x0001a] in /Users/alan/Projects/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/Mono.TextEditor/Gui/TextArea.cs:228 
    at (wrapper managed-to-native) System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod,object,object[],System.Exception&)
    at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System.Reflection/MonoMethod.cs:305 
     --- End of inner exception stack trace ---
    at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00043] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System.Reflection/MonoMethod.cs:313 
    at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/reflection/methodbase.cs:229 
    at System.Delegate.DynamicInvokeImpl (System.Object[] args) [0x000e1] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System/Delegate.cs:463 
    at System.MulticastDelegate.DynamicInvokeImpl (System.Object[] args) [0x00008] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System/MulticastDelegate.cs:67 
    at System.Delegate.DynamicInvoke (System.Object[] args) [0x00000] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System/Delegate.cs:408 
    at System.MulticastDelegate.DynamicInvokeImpl (System.Object[] args) [0x0001b] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System/MulticastDelegate.cs:72 
    at System.Delegate.DynamicInvoke (System.Object[] args) [0x00000] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/mono-x64/mcs/class/corlib/System/Delegate.cs:408 
    at GLib.Signal.ClosureInvokedCB (System.Object o, GLib.ClosureInvokedArgs args) [0x0007f] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/gtk-sharp-None/glib/Signal.cs:207 
    at GLib.Signal+SignalClosure.Invoke (GLib.ClosureInvokedArgs args) [0x00019] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/gtk-sharp-None/glib/SignalClosure.cs:114 
    at GLib.Signal+SignalClosure.MarshalCallback (System.IntPtr raw_closure, GLib.Value* return_val, System.UInt32 n_param_vals, GLib.Value* param_values, System.IntPtr invocation_hint, System.IntPtr marshal_data) [0x00053] in /Users/builder/jenkins/workspace/build-package-osx-mono/2018-02/external/bockbuild/builds/gtk-sharp-None/glib/SignalClosure.cs:143

Seems like TextViewLines is null.

VS bug #583112

mono / monodevelop

Diff editor does not work anymore #4160