altgr removes the ability to delete text in text editor

[ravengalqueen]

Im testing floem to see if it would be adequate for a project im working on, while testing i fount that typing "{" would remove my ability to delete text, while still allowing me write text. After further testing i found out this was also affected by ²³[]}, to later realize all of those are key combinations utilizing the altgr key (in a german T3 keyboard which is what i use).
I used a slight variation of the example syntax editor, changing the apply_attr_styles function to work better with multiline comments, further testing indicated this was not the issue. Im really curious as to why this happens