GitLab

Only call value_changed_fn when the value has changed during null poll events, in line with the check for change logic in Increment().
Note that steppable_set_value() still sends one event per call as mentioned in the cautionary note at line 535, so when called programmatically the behaviour is unchanged.

Tested on a Raspberry Pi, no more shimmering colour swatches.

Version 0.55. Tagged as 'Picker-0_55'