Hi and thanks for your attention.

I am in: Settings > Custom Shortcuts > Custom Gesture > Action

I see options here under "Window" to limit the windows where this gesture is effective, but none of them work in an expectable way. What I have tried is:

1. Assign gesture (Ctrl+s)
2. Set Window > Specific Window
3. Set Window > New > Window Title "Contains" > Kate

But it still tries to save pages in Firefox and so on. :\

PS: Note that "Custom Gesture" will be created with Edit > New > Mouse Gesture Action and will not appear until you create one manually.