Disable subscription item value decorations/coloring by default, enable via preference page
Currently SubscriptionItemLabel and SubscriptionItemLabelDecorationRule cause performance problems in cases where there are lots of subscription items in a model and model browser is expanded to visualize those nodes.
This will cause the tree node -related DB queries to depend upon the everchanging/triggering experiment-context values of the Variables referenced by the subscription items and therefore get constantly invalidated for DB query re-computation.
By default especially the value reading must be disabled to avoid large performance issues with models containing hundreds or thousands of subscription items.
The labeling implementation shall be changed so that the (INVALID)
suffix shall be calculated already in SubscriptionItemLabel
, not SubscriptionItemLabelDecorationRule
to be able to just skip the whole decoration rule in case the preference to-be-introduced is disabled.