one key switch between source screen and gdb screen?

**Is your feature request related to a problem? Please describe.**
I am frustrated when I launch the executable and key in gdb command yet resulted in weird action. Also a quick way to bring me back to gdb command window is highly expected

**Describe the solution you'd like**
I want the default curse focus be set on the gdb command line when the exectutable is first launched.
I want a hot key to bring the curse to gdb command window no matter where it is.

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

**Additional context**
Add any other context or screenshots about the feature request here.