Changes in torrc are applied via SETCONF control command. If the "Save settings" checkbox is check, it issues a SAVECONF control command.
So, does this happen the same if you issue a SETCONF control command by hand?
No. But clicking 'OK' in Vidalia's 'Settings' dialog sends SAVECONF, and nearly all users will click 'OK' there after they finish using the 'Edit current torrc' dialog.
A glance at the master branch's code (0.2.21) revealed that the application has not been designed to deal with a 'temporary setting' : SAVECONF is called in ServiceSettings.cpp, ConfigDialog.cpp and TorrcDialog.cpp. ConfigDialog should be the only one to handle the SAVECONF command otherwise the service editing & the torrc editing override each other - because it iterates through a stack to save the whole set of pages -, thus the undesired behaviours which occur when a SAVECONF is issued after a SETCONF.
Since the feature is not really essential and seems to have disappeared from branch alpha (0.3.3-alpha) I also suggest to remove the checkbox from the TorrcDialog.ui in the current branch master.
Would deleting the checkbox from TorrcDialog.ui (using Qt Creator GUI)
be both sufficient & necessary or any other changes would be required in
addition to that?