Commented Unassigned: Really slow on bigger project [4740]

Hi,

This is great tool, but unfortunately on our bigger project is nearly unusable.
We have 1700 resource keys in approximately 100 resource files.

When I open ResxManager, visual studio hang to nearly 10 seconds.
Next action unselect all resources, hang next 10 seconds. Practicaly every change selection do this hang.

When I try scroll resources and some name are too long. The ResXManager change layout to show full name, but hang another 5 seconds before change layout.

I profile this preformance issue and attach results .

Results was measured during this sequention actions:
- unselect ALL resources
- select ALL resources
- Scroll from start to end resources
- Scroll from start to end resources

In attachments are unrolled two biggest method.

Thanks .
Comments: Associated with changeset 37373: Improve loading performance: Grouped collection view was created and updated always. Create it in code on demand, not via CollectionViewSource in the resources.