Whose a window is that someone else shared with the workspace, as the
bar of the window it opens here says while the window is in front: their
name, “Ana’s window”, with their face.
Who can see a window its person shared with a workspace where each
person lays out their own windows: the workspace, by name, and the people
in it now, as the window’s bar says while the window is in front.
Whoever opened a tab on a shared desktop, when it is not this desktop’s person and they may not
rearrange it: no close, a drag that springs back, and hovering names them.
What a tab’s content is doing, marked in place of its icon: loading, or making sound. A sound
mark is a control, and a click is reported by TabBar::take_mark_click.
A window’s application mark at any size: the app’s own artwork when it
has some, else the app-kind glyph its tab pill wears, scaled up from the
pill’s 14 px design size. Every surface that names a window by its app
(the tab pill, the window switcher, the overview) paints this one mark.
A point packed as the one number an event’s at carries: y in whole
logical pixels above x, each below a million, so a window’s coordinates
survive the round trip.