Behavior of Ctrl+T with map annotation tools is hard to understand

[qgib]

Author Name: Harrissou Santanna (@DelazJ)
Original Redmine Issue: 18589
Affected QGIS version: 3.1(master)
Redmine category:map_canvas

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QGIS documentation says:

If you press Ctrl+T while an Annotation tool is active (move annotation, text annotation, form annotation), the visibility states of the items are inverted.

I don't pretty understand what it means but this is another issue...
I neither understand how this tool works in the map canvas: what decides which annotations are hidden or not?
I added many annotations to the dialog and I'm unable to understand why visibility of half of them is toggled on/off when i press Ctrl+T and I cannot see how I can edit the list of impacted annotations (set some of them to stay always visible, or make anothers "togglable").

[roya0045]

@DelazJ Is this still viable? Should this be moved to doc instead?

[YoannQDQ]

Ctrl+T was dropped in #53015.