However, there is currently no way to bring up this menu in, for example, a GTK app which uses client-side decorations!

This isn't true, given that GTK apps send the required wayland-request on their title bar to make cosmic-comp open the menu.

However there are windows completely devote of decorations and some less known or cross-platform toolkits, which don't do this.

@maria-komarova I have thought about how we could implement this without loosing resize, given this is an issue for e.g. Firefox Picture-and-picture windows (something many people probably want to be sticky, which currently can only be done through the shortcut).

I think this is a decent proposal, though I also thought about using Super+Middle-Click, however not every pointer device does have that button. Any opinion from a UX perspective?

I'd try to avoid using middle click for the reason you mention - not every pointer device has the button. So using right click on press and release seems like a better option. I might be missing some potential concerns but I can't yet see them.

This isn't true, given that GTK apps send the required wayland-request on their title bar to make cosmic-comp open the menu.

My mistake, you're right. Firefox was the case I noticed it not working in, but it makes sense that they'd be doing their own thing.

This isn't true, given that GTK apps send the required wayland-request on their title bar to make cosmic-comp open the menu.

My mistake, you're right. Firefox was the case I noticed it not working in, but it makes sense that they'd be doing their own thing.

Note for firefox specifically: You can do a second right-click and it will work.

But we will implement this (eventually).

Is there a shortcut for "Always on top"? Sticky will keep the window even when you change workspaces.
I'm curious if there is a "Always on top" action and if it could be assigned to a shortcut (since probably exposing it in the context menu would cause confusion with the sticky window feature).

Is there a shortcut for "Always on top"? Sticky will keep the window even when you change workspaces. I'm curious if there is a "Always on top" action and if it could be assigned to a shortcut (since probably exposing it in the context menu would cause confusion with the sticky window feature).

Would be cool to have such an option. Maybe it could also work then the way it does on GNOME: #534

I'm curious if there is a "Always on top" action

No. This concept is not present in cosmic-comp and we don't have an action for it.