Currently, the act of Ungrouping a large collection of Elements causes two issues:

1) A Long Hang as the Ungroup process runs

2) A 'permanent' performance degradation of Studio and sometimes a permanent hang of the application after the Ungroup process has completed.

See attached video.

Repro Steps:

1) Open the 'MiniShowcases' Sample, then open '3DTransformations.xaml' contained within.

2) In the Navigator, expand Page/Grid/HUD/[Canvas]/Dots

3) Select the "Dots" Grid, and press Ctrl+Shift+G to Ungroup it.

Observe how a long hang occurs.

Eventually, the Ungrouping will complete.

4) In the Navigator, scroll all the way to the top of the hierarchy, and select any Element (The 'HUD' Grid works well)

Observe how Studio enters an infinite hang, is seemingly unable to recover, and the application must be forcefully exited.

Expected Results: Ungrouping large groups don't cause application freezes.