Listbox bug or feature for Language keyboard

I use multiple languages and noticed that Listboxes change my language keyboard (English, French, etc) automatically and only with listboxes. I found a setting in the Mac Keyboard Preferences that doesn’t make that happen and since it only is with a Listbox (not textareas etc), I wonder if it is a feature or bug. The setting is “Automatically switch to document’s input source”. If checked it switches out of the chosen language and only on a listbox. Which is it?

Are you talking about when you go to edit a cell?

I am sorry for not mentioning I was editing. Yes with editing. I have experimented with the Listbox problem before by creating a separating app and it didn’t happen. It didn’t change input language. I didn’t know what caused it to shift before.
Also it has only happened with Listboxes and not Textareas.

What about TextField? Listbox spawns a TextField above itself for editing cells.
I’m surprised TextArea isn’t causing the keyboard switch.

I finally figured out how to easily test a textfield for this problem. My thinking at bedtime isn’t always bright.
The textfield does NOT have the input language problem.
I also realized my app has several other listboxes and I could easily change the readonly property.
The newly made ReadOnly = False Cell automatically changes the input language.
Suggestions for further debugging?