Unable to load/Edit interface - Will not open expression editor pane.

Are you only seeing this on this one expression? Does the expression call other rules?
I suggest starting with the "children", as well as checking your avail memory for your server.

Thanks for the response. This is an interface that is the base for a report I'm building. So far it is the only piece.

And as far as the server. Everything else in designer/tempo is working correctly. I'm having trouble with this one interface specifically, but so much trouble that I can't even open the expression editor to start trouble shooting and locating the source of the excess memory demand.

Anything in the logs?
Do you have many loads (but if you can't get in to comment some put, doesn't help :-( )

Ben,
What is the source of your report?
Data from DB or a Portal Report?

Data from a DB view. View works fine in SQL Server

Can you check the performance for the Query rule which is used to retrieve the data from DB View?

You will want to make sure you are setting the batch size and not trying to pull all data at once.
How many rows are returned in the view?

Ben Hulet As per my understanding, I think you are having a rule (Either QueryEntity, or a QueryRule) which pulls the Data from view, and you might be using this rule inside interface. So can you execute that rule separately instead of directly using through Interface, so that we can conclude, is the Interface performing slow, or the the QueryEntity/QueryRule, if this rule also takes much time to execute and return the response, then try to do batching and pull limited rows as per the requirement as ChristineH also has mention. If after batching also its working slow, and taking huge time to return the response then i suggest, try checking the View, does that view contain some complex query/logics which gets evaluated for each single row return by it. But if the QueryRule/QueryEntity is returning the response from View quickly, then only there might be some issue in your interface.

So i suggest perform these test cases to conclude where exactly the problem is(whether in Interface, QueryEntity/QueryRule or inside View), so that we can quickly resolve this

Yes, your response best sums up the problem. I was using apply(rule!queryView) which was very slow and could have been sped up by limiting the batch size. But I was able to amend the view to include the data that I needed in the interface.

Thanks All for the support.

Ben Hulet Happy to hear that your problem has been resolved.