When creating a new card type, based on the Basic card type, I encountered a program state that has no apparent way to save my changes.
Starting from the basic card type, I modifying the note type fields as follows:
- Added several new fields
- Deleted the “Front” and “Back” fields. (shown below)
- Hit “Save”
The following dialog appeared:

I’ve tried readding “Front” and “Back” fields to the card type, but the same dialog appears when I try to save.
Here is my version info:
Version <U+2068>2.1.61 (5ad29c37)<U+2069>
Python 3.9.15 Qt 6.4.2 PyQt 6.4.0
As a side observation, the word “Yes” is clipped in the dialog that appears when you cancel changes to a note type fields:

