It happens, when I resize the window below a certain width. If I keep it open like that it seems to be happening every time, the window is being re-rendered. I followed your advice and turned off all the filters, so that there was nothing in the list; it didn't happen then.
I also enabled logging to Output window. Every time the memory consumption spiked, there was an OutOfMemoryException logged in the Output window, unless Visual Studio crashed. Here are two of them:
[10:53:16.5355-UI-1] ERROR (Internal): System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
at System.Collections.Generic.LinkedList`1.AddAfter(LinkedListNode`1 node, T value)
at NCrunch.VSAddIn.UI.TextDisplayControl.SplitTextContent..ctor(String content, Int32 maxLineLength, IList`1 hyperlinks)
at NCrunch.VSAddIn.UI.TextDisplayControl.TextDisplay.#=qGSGTWkQNY2kpk80EcsPwNpD24mCxC49a98wrR3IR8mE=()
at NCrunch.VSAddIn.UI.TextDisplayControl.TextDisplay.#=qGn0Nyw$MZfgpGdRkg_$P3Q==()
at nCrunch.Common.ErrorHandler.DoWithErrorHandling(Action action, Object context)
[11:01:26.5325-UI-1] ERROR (Internal): System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
at System.Collections.Generic.LinkedList`1.AddAfter(LinkedListNode`1 node, T value)
at NCrunch.VSAddIn.UI.TextDisplayControl.SplitTextContent..ctor(String content, Int32 maxLineLength, IList`1 hyperlinks)
at NCrunch.VSAddIn.UI.TextDisplayControl.TextDisplay.#=qGSGTWkQNY2kpk80EcsPwNpD24mCxC49a98wrR3IR8mE=()
at NCrunch.VSAddIn.UI.TextDisplayControl.TextDisplay.SetContent(String content, IList`1 hyperlinks)
at nCrunch.VSAddIn.UI.TestTree.LinkedOutputText.ApplyToTextDisplay(TextDisplay textDisplay)
at nCrunch.VSAddIn.UI.TestTree.TestsWindow.#=q1jsKORUTV365ycPrrX_UpWGVN_lGVMpwm3od7OdPDVE=()
at nCrunch.VSAddIn.UI.TestTree.TestsWindow.#=qyTUshAyxncThR5sVu_CfUvZSa0jDRO5GkqDI8KFXyoU=()
at nCrunch.VSAddIn.UI.TestTree.TestsWindow.#=qXh4RBEdbhNe$xdZXbUrMWyheqCowogzjwwMxRyM6I_s=(Action #=q2vPU17HO5WTRRANNRxBmaw==)
Strangely enough, the window still seemed to be properly rendered after this exception.
Regarding the build errors: they are logged to the output window and they are displayed in the Processing Queue window. They just don't show up in the NCrunch Tests window. but there are no exceptions logged when I have it open wide enough and build errors are being logged. Could I somehow turned that off? It's not that much of a problem though, since build errors are listed in Visual Studio's Error List window anyway.