Adjust BPM by uneven factor / re-enable constant tempo broken when assume constant tempo is disabled.

[LeonTheOriginal]

Bug Description

When "Assume constant tempo" is disabled, the uneven BPM multiplication options (2/3, 3/4, 3/2, 4/3) are not working. (Double / Halve are working normally.)
Also (re)enabling "Assume constant tempo" for a single track in its properties is ignored unless the BPM also has been edited manually.
This bug seems to be introduced with version 2.4.x. Version 2.3.6 is unaffected.

Version

2.4.1

OS

Windows 10

[ronso0]

When I try to reproduce I see these warning being logged

warning [Main] Marker with 117 beats till next marker cannot be scaled by 0.75
warning [Main] Marker with 67 beats till next marker cannot be scaled by 0.666667
warning [Main] Marker with 117 beats till next marker cannot be scaled by 1.5

However, this has not been changed by the last commit that touched the scale function 3 years ago 9dbe081
which makes me think that

Version 2.3.6 is unaffected

is true for tracks where by chance the beat counts allow division/multiplication.
Did you test 2.4.1 and 2.3.6 with identical tracks?
(though even that may mean nothing if the beat analyzer yields different results)

[ronso0]

Also (re)enabling "Assume constant tempo" for a single track in its properties is ignored unless the BPM also has been edited manually.

Yes, the UX with this option should be improved.
The checkbox is active (can be changed) only if the track has a beatmap (last analysis was with const tempo off).
Un/ticking the box alone does nothing:

• if you tick it, you need to tap the BPM in order to create a beatgrid
• if you untick it, the track has to be re-analyzed to get a beatmap

For both convertions, the track menu's "Re/analyze" actions are more suitable.
Shall we add these àctions to the BPM tab in Track Properties?