I noticed a bug where you could press the "Switch lesson" button multiple times before the window was set invisible, making it create multiple dialogs. I just switched the two lines, setting the main frame invisible BEFORE creating the dialog, seems like fixing the bug.
Could you maybe shorten a bit the button text so that the whole toolbar still fit in the default size of the PLM window? Or maybe increase a bit the size ?
I noticed a bug where you could press the "Switch lesson" button multiple times before the window was set invisible, making it create multiple dialogs. I just switched the two lines, setting the main frame invisible BEFORE creating the dialog, seems like fixing the bug.