I think that RevParse should be called lazily like in [left-panel branch](https://github.com/gitextensions/gitextensions/blob/feature/left-panel/GitUI/CommandsDialogs/BrowseDialog/FormGoToCommit.cs#L30). Forms hungs up for a while when you paste  `feature/DistSettings#gitex://gotobranch/feature/DistSettings` and delete chars from begining.