PlasmaTheme: only sync colors when parent item is visible
visibleChanged can also be signalled when an item is being destroyed, but syncing colors when an item becomes invisible doesn't make much sense.
SENTRY: PLASMA-WORKSPACE-Z6
visibleChanged can also be signalled when an item is being destroyed, but syncing colors when an item becomes invisible doesn't make much sense.
SENTRY: PLASMA-WORKSPACE-Z6