IO mega issue

[GrayWolf64]

BUG: popups go under the window when clicked, when the window is not inside the main vp
TODO: the code looks ugly

[GrayWolf64]

TODO: instead of blocking TextEntry keys that can move cursor, can just SetCaretPos to tail everytime? should check vgui2/vgui_controls/TextEntry.cpp

BUG: sometimes the first character attempted to type will be eaten by something else, but not the InputText
NOTE: Facepunch/garrysmod-issues#2886

EDIT: first TODO done