I have been upgrading my Android dev environment so that I can work with the new 2.1 SDK. At the same time I thought I would update Eclipse. Unfortunately, this caused an isBlockSelectionModeEnabled error whenever I tried to edit an XML file.

It turns out that WST XML 3.1 can’t be used to edit Android XML files. The solution is to use ‘Revert Configuration’ back to WST XML 3.04. If you have just installed Eclipse then you won’t have anything to to revert back to so I suggest to try an earlier version of Eclipse.