Hi Bones,

it's a known bug that windows don't react on changing their WF_SHOW flag. As a workaround, you have to make its panels and children manually invisible. This will be fixed in the update I hope to release this year.

Windows SHOULD be destroyed when you click on their x button. A reason it doesn't may be because you call LBG_stop_action in its Close function, if you assigned one, but that shouldn't make it invisible...
Or maybe you checked its WF_DONTDESTROYCHILDS flag, so only its children are still there. I don't know how it "seems to be still there" exactly, so I can't guess further than that.

I could not reproduce the combobox/listbox issue. It works fine for me. Maybe the problem is in your code?