#3 Switch / Update buttons should be locked after the first click

[Bogdan Grigore]

If a user uses double click on the Switch to trunk / Switch to branch / Update buttons, both of the requests will be executed and the user will be shown the results of the second request only:

svn: Working copy '.' locked
svn: run 'svn cleanup' to remove locks (type 'svn help cleanup' for details)

In order to avoid such a situation, we should lock the buttons mentioned above after the first click has been used on the.