More specifically, this fixes placement blueprints not beginning placement when using touch input while the cursor was previously outside compose area, due to the placement blueprint not existing (removed from the scene by `ComposeBlueprintContainer`).
This is in addition to Shift + Right-click.
I thik middle mouse feels more natural and is a good permanent solution
to this issue.
Note that this also *allows triggering the context menu from placement
mode*. Until now it's done nothing. This may be annoying to users with
muscle memory but I want to make the change and harvest feedback. I
think showing the context menu is more correct behaviour (although
arguably it should return to placement mode on dismiss?).
Until now, these were haphazardly enforce inline in blueprint
implementations. The only thing stopping complete breakage is that
`EndPlacement` wasn't called (too much) from outside the blueprint,
leaving them responsible for their own placement.
By moving this conditional out of the provided paramters to
`EndPlacement`, it allows more flexible usage of that method externally.
Coming in a future PR.
Similar to velocity / difficulty points, a user expectation is that
volume and sample settings will be transferred to newly placed objects
from the most recent one.
Closes https://github.com/ppy/osu/issues/18742.