Revision grid suddenly change selection after finish loading revisions

[azarkevich]

Actual for GitExt 2.49 and master

On big repository refreshing (F5) revisions graph consist of 3 steps:

1. Loading revisions and show 'Loading ...' message
2. Show some revisions and continue loading
3. Finish loading and restore selection

Here is enough time between step 2 and 3, so usually I able select some revisions, open context menu and... suddenly selection changed and I should close context menu, goto back to desired revision, click it again...

[azarkevich]

I fix it temporary in 27585a0 for my patched version, via disabling step 2, but seems correct solution will be in save selection during phase 2 and restore it in 3. I try this approach but without success.