Setup: Today I was editing the comment in an existing task and was interrupted by a reminder. I chose the wrong choice (I discarded my changes) After that mistake I started to CTRL+S my changes frequently. The issue: This task has a custom Category After I left the editing process I noticed the Category column entry for it in the CTRL+Shift+D task listing view had many copies of the custom Category I'd created for it. I reopened the task to edit and de-selected the custom category, CTRL+S, and they all went away. I RE-selected the custom category, CTRL+S, and it reappeared one single time. I clicked [Save and Close] and the custom category now appears twice. Along the way I noticed it duplicates the custom category in the Tasks display for every time I CTRL+S while I'm editing the description. I successfully eliminated the custom category > saved > closed task > reopened task > recreated custom label ... the duplication behavior continued. I think this is enough information to recreate the behavior. If not, let me know - TIA Windows 10 64 bit up to date Thunderbird 78.9.1 (32-bit)