Portal highlight for many to many
I've been trying to do this for a few hours now and I'm going round in circles.
I have 2 Tables and am making a many to many relationship operated via portals.
One Side1 (call it Groups) I want to be able to make a selection of side2 (call it Items) that is record specific. So each record in Groups has its own selection of Items. This bit is easy and works fine.
What I'm having trouble with, is using conditional formatting to make the portal rows for Items (on the Groups layout) change colour for the Items that have been selected and appear in the Groups portal.
I can do it for a single record in Groups using a simple match field in Items (an 'equals' calc) but I can't understand how to do it for multiple records in Items which feature in multiple records in Groups.
Can anyone help me with this?