`ViewPrivate::contextMenu()` has a surprising way of handling the `ktexteditor_popup` menu aboutToXXX signals: it disconnects them from the current ViewPrivate instance and then reconnects them to the same instance.
I think the disconnect should be from all receivers that were once connected to the menu show & hide signals. Doing that resolves the issue where `ViewPrivate::aboutToShowContextMenu()` is called for all open KTextEditorViews that once had the context menu open, instead of only for the view that is currently active.
BUG: https://bugs.kde.org/show_bug.cgi?id=401069