I know this is pretty simple matter but I think it’s gonna be more convenient if you put this little tab ( Maybe the buttons too if possible ) to the left so it will not block the menu tab from the right.
As far as I know, it’s the operating system that does that.
There’s no room to open the first level submenu to the right, so it opens to the left, then there is space for the second one and it opens to the right as it should be by default.
I may be wrong but I don’t think applications have control over this behavior.
I agree it’s annoying at times.