This is a rather minor, but nonetheless very anoying bug.
Quite simply, the chat will constantly become selected, causing any hotkeys you use to be simply written into the chat instead. I have tested this quite a bit and found that this happens when you close a window, like your inventory, a container or the stats window. However only if that window is the one you last clicked within. For exemple, if I open my inventory, move an item and then close it, the chat will be selected. This also happens even if I only click the edges of the window or an open slot.
I would asume there is a variable holding the window you last selected, that always defaults to the chat. It should therefore be very easy to fix by just setting the default to something else.