VS2017 freeze when CSS code is highlighted

[ThinkElevenDave]

Installed product versions

• Visual Studio: 2017 Professional
• This extension: 1.1.23

Description

When highlighting code within a

Steps to recreate

1. Open webform page
2. Create some css rules within a CSS block (not external style sheet)
3. Close and reopen file
4. Start to highlight the css rules
5. IDE freezes

Current behavior

IDE freezes. Possible explanation from ActivityLog.xml shows this:

System.Runtime.InteropServices.COMException (0x8001010E): GetService must be called on the UI thread.
at Microsoft.VisualStudio.Shell.ThreadHelper.ThrowIfNotOnUIThread(String callerMemberName)
at Microsoft.VisualStudio.Editor.Implementation.Common.GetService(IServiceProvider serviceProvider, Guid guidService, Boolean unique)
at Microsoft.VisualStudio.Editor.Implementation.Common.GetService[InterfaceType,ServiceType](IServiceProvider serviceProvider)
at Microsoft.VisualStudio.Editor.Implementation.ShimLanguageNavigator..ctor(ITextBuffer textBuffer, ITextStructureNavigator delegateTextStructureNavigator, ITextStructureNavigatorSelectorService textStructureNavigatorSelectorService)
at Microsoft.VisualStudio.Editor.Implementation.ShimLanguageNavigatorProvider.CreateTextStructureNavigator(ITextBuffer textBuffer)
at Microsoft.VisualStudio.Text.Operations.Implementation.TextStructureNavigatorSelectorService.<>c__DisplayClass14_0.<CreateNavigator>b__0(ITextStructureNavigatorProvider provider)
at Microsoft.VisualStudio.Text.Utilities.GuardedOperations.<>c__DisplayClass19_0`3.<InvokeBestMatchingFactory>b__0()
at Microsoft.VisualStudio.Text.Utilities.GuardedOperations.CallExtensionPoint(Object errorSource, Action call)

Expected behavior

IDE should work as normal.