Bug explanation

Bad Dialog:

Good Dialog:

To Reproduce

This is easily one of the weirdest bugs I've ever encountered. Download my repo if you want to follow along: https://github.com/jrdnwrth/ButtonBugExample

1. Enter a value into this TextBox:
   
2. Click the "Open Buggy Dialog" button.
3. You will see the Bad dialog.
4. Clear the text box.
5. Click the button again.
6. You will see the Good dialog.

The Plot Thickens

Want to fix the bug? Change the Width of the dialog from 160 to 170. No more bugs. All fixed. I kid you not.

Also notice that Visual Studio's "UI Debugger" widget at the top of the popup disappears when it is broken:

I'm not sure what that is about.

More info

• I am seeing this bug in v4.8.0, v4.9.0, and v5.0.0 preview.
• This bug only shows up in dialog windows.

Version

4.8.0