I'd like a switch to be added that will properly close the app. Specifically, I'd like to see this added to the Thunderbird Portable launcher, but I think it would be a good feature for all launchers.
I'm using SmithTech's Portable Startup Utility (hereafter referred to as PSU) to handle autorun on my flash drive, with PAM and TBP set to launch automatically. I have the MinimizeToTray extension installed in TBP; it launches minimized and sits in the tray when I'm not reading or typing an e-mail. In addition to commands you wish to execute at launch, PSU has the option of running a separate list of commands when PAM is closed as a "cleanup" routine. Now, I really don't think I'd forget to close PAM since I'm using my "PortableApps platform is active" background with the wallpaper switcher, but I sometimes forget to close TBP before attempting to safely remove my drive (which, of course, fails until I do close TBP). This would be one less step I have to take when leaving a PC if the TBP launcher had a switch like "/close" or even just "/x" that would properly close TB. That way, I could just add (for example) "TBP-path\ThunderbirdPortable.exe /x" to PSU's cleanup routine.
I do know of a command-line utility that will end a process, which, if used to kill thunderbird.exe, would cause ThunderbirdPortable.exe to close as well, but that isn't what I'm looking for. Firstly, I don't like killing a process unless it's unresponsive. And second, if TB still happens to be minimized, that little Windows bug that doesn't get rid of the tray icon for a killed process until you move your cursor over it will kick in. (I'm surprised Microsoft still hasn't fixed that in Vista SP1.)
Additionally, though it isn't necessary, using the close switch could trigger a confirmation dialog instead of immediately closing the app. I know there are probably people out there who wouldn't like it if a single command line could be used to close an app without some kind of confirmation from the user.
Oh, and if the TBP launcher (or others) already has a close switch of some sort, I'm sorry for reposting the suggestion. However, I did a fair bit of searching and couldn't find any evidence that such a feature existed, nor that it had been requested before.