Selection history should be global

[abey79]

Currently, the selection history is stored on a per-recording basis. However, with recent changes, this make no longer sense:

• Blueprints are also recordings, and having a selection state there is meaningless.
• Recording (and soon even AppIDs Make App ID selectable #5672) can now be selected. Since that also changes the current recording, the selection history becomes meaningless in that case.

To repro the behaviour:

• open multiple recordings
• select first recording
• select a bunch of things from that recording
• check selection history (right-click on back icon) -> notice there is stuff there
• select another recording
• check selection history -> such empty...

[nikolausWest]

How does that play with a future ability to set selection state from code?

[abey79]

How does that play with a future ability to set selection state from code?

If anything this might make it actually easier since there is now a single place where the selection states lives.

Unrelated: this is technically a functional regression. Before, we could have a different selection state for each recording (e.g "/world/robot" is selected in recording A and "/world/camera" is selected in recording B). However, in practice that's no longer true since recording have been made selectable: switching to a new recording now implies selecting said recording, in turn clearing the selection. This issue would make it harder to go back to the previous behaviour.