FileOpen performance with many targets

[jmthomas]

When many targets are installed the initial FileOpen dialog can take several seconds building the list of files across targets. The initial list should only include the list of targets and then as targets are expanded the file list can be updated.

[jmthomas]

This is tricker to implement than I initially thought because of the search box in the file tree view. It basically only works if all the data is there in the tree.

I think the solution is to first load all the targets. Then only load files for a target when that target name is clicked. The search will only search through the loaded targets. This is a regression of sorts from the current behavior but with a large number of targets I don't see any other way.