It is impossible to know about all bugs in the current build. New bugs that appear in several branches are found quite often. Therefore it is important to be able to enter new bug into several branches at once. Care should be taken of branches new bug should be entered into. In open-source projects we cannot rely on a good will of the external user to try whether this bug appears in other branches.
Some rules have to be established about branches that probably contain the new bug.
New branch of bug can be created. Sometimes can happen that bug was entered into more specific branch that it should have been entered. In such situations it should be possible to branch just one bug report. User can find bugs in specified branch. Users should be able to find all open bugs in their installed version.