Pasting code into wrong file

After switching modes from Design to Edit, an interesting issue with text editor hotkeys may occur.

Steps to reproduce:
1. Open any .qml or .ui.qml file in Design mode.
2. Open any text/code file not supported by Design Mode - for example .qmlpoject. It will open Edit Mode instead of Design Mode.
3. Try to paste, copy or use any other hotkeys in newly opened file - nothing will visually happen.
4. Now check your previously opened .qml file - all the pasted code will be in that file, likely on the first line with import, or whenever text input cursor was.

I guess that this issue appears due to Design plugin still executing somewhere in the background and its Text Editor still running and capturing hotkeys. Design plugin executing also causes Binding Editor and other Dialogues not to close on leaving Design Mode.