Shortcut Ctrl/Cmd+A doesn't work after clicking a textbox

[jesse-wei]

If the GUI is focused on a textbox (this will occur if you click a textbox or do File > Open or File > Add images any time after the first time) and then use Ctrl/Cmd+A, the shortcut won't work (at least on my Macbook). This is probably because Ctrl/Cmd+A is mapped to "Select all," which already has a function inside textboxes.

We should change the shortcut (easier, ofc) or make the shortcut work even when the GUI is focused on a textbox.