TiddlyDesktop window cannot be closed when creating new wiki but forgetting to add .html file extension

[catscratchedme]

I'm running TiddlyDesktop 0.0.14 on Linux Mint 20.3.

Problem:

1. When I click
   Create new wiki > Empty Tiddlywiki file
   It brings up a file-picker dialogue that lets me name the new TW file.
2. If I forget to add the .html file extension, TiddlyDesktop will open the new TW file, but it appears as the HTML code.
3. I cannot close this window by clicking the close button, and I need to quit the whole TiddlyDesktop app to close that window.
   

Expected Behavior:
Allow the user to close the new TW window if they forget to add the .html file extension during the new TW creation.

[Jermolene]

Ouch! Thanks @catscratchedme, I've actually run into the same problem myself.