The problem is sometimes you upload a version where you forgot to check something and than it isn't possible anymore to delete it.
Branislav Nisic commented
I can't believe that this is actually something that was not implemented from the start. Uploading the revision to the wrong design seems like a mistake that can happen easilly. Not having a way to fix this mistake (other than reuploading the correct previous revision) is really anoying.
It is becoming extremely problematic that we cannot delete a revision within a Design folder.
Agreed. Sometimes, you could even upload your file in the wrong directory and therefore have a screen in your revisions list that is not meant to be.
Being able to delete a revision in order to keep everything clean in case of errors, is pretty much the least expected.
Its not like we are on GitHub committing code ! :p