Not able to bind key combination in gnome-flashback

[Rahul Ghanate]

I am using Gnome Flashback with 18.04,
Whenever I run glipper I get below errors,

Binding shortcut <Ctrl><Alt>c to popup glipper

** (glipper:21260): WARNING **: 16:30:12.450: Binding '<Ctrl><Alt>c' failed!
Changed process name to: glipper

It is not able to bind keycombination.
It's not about the same keycombination is being used, I can set any other command binary to bind to that key combinations in keyboards->shortcuts settings.

I tried with every possible key combination which can be bound but it is not binding anything at all.
<Ctrl><Alt>c
<Ctrl><Alt>v
<Ctrl><Alt>h
<Ctrl><Shift>g
<Ctrl><Shift>c
<Ctrl><Meta>c
<Ctrl><Meta>x

And stage thing is the key combination and glipper works fine in other desktop environment like budgie-desktop or deepin.

It must be gnome-flashback issue which need to be handled in glipper code.