NullReferenceException when using tabs in AvalonDock

[startere]

NullReferenceException gets thrown at System.Windows.Interop.HwndHost.BuildWindow() (using AvalonDock), you can see AvalonDock code in the callstack.

See attached file for the callstack:
https://github.com/xceedsoftware/wpftoolkit/files/3329940/BuildWindowNullReferenceException.txt

No stable repro at this time. Most probable repro is saving files opened in the application. The files are represented by tabs docked in the app.

Dump:
https://mega.nz/#!Xu4lWajL!XkARTj0SAS8ozk79gp-pMq-BYe8E6zGQd4XrlyQ4ohw

[Dirkster99]

You'll probably get:

• a text like this or
• a text like that

as answer for entering an issue here and you'll have the choice of waiting (for months or years) or paying money if you want to stick with this project...

Many users of this repro are now thinking that the open source release of the toolkit is no longer maintained. See this thread for a related discussion.

Because of this situation I have started my own AvalonDock branch.

So, I am wondering if your problem is related to version 3.5?

Because we already fixed a number of critical issues in this release and you would not be the first:

• #1501
• #1499
• #1498

to find out that a fix is well known but not implemented in this project's open source version.

Can you please test with this Nuget version and give me detailed feedback containing a workflow description (possibly with one of the test applications in my repro) to either:

• confirm the problem or
• confirm that you cannot reproduce this problem in my branch?

[startere]

Thanks for the detailed response and advice. Initially, I'll try with the fix from the links you mentioned:
Dirkster99/AvalonDock@f966d6c
If the issue appears again I`ll try switching to your Nuget.