HandBrake

Please describe what you would like to see added to HandBrake:
When rearranging lots of subtitles for conversion, the ones that are (accidentially) double listed by user appear in red color.

Why would you like to see this added:
As you don't want to insert a subtitle twice but may want to rearrange the list of many subtitles, it would help to prevent double listing.

What version of HandBrake are you currently running:
1.0.1

What operating system and version are you currently running (e.g. OSX 10.11, Windows 7, Ubuntu 14):
OS X 10.11.6

Since handbrake doesn't do "rearranging subtitles", are you meaning "source files (titles) added multiple times to queue"?

No, I actually can add a MKV file containing several subtitles, select MKV H.265 for output format and choose the order in the menu "subtitles", I can even add for example subtitle #2 as often as I like. Do you need a screenshot of it?

OK, I understand what you're saying now, but...

Adding subtitle 2 (your example) multiple times is not necessarily an error requiring it be colored red.

My example: If I want to use the forced subtitles in track 1 as the default, but several of my players don't understand forced subtitles, I'll add track 1 twice; once with "forced only" and "default" set, and once with no options checked. And the order it is set is important for the players in question, because they also don't understand "default" - they just play whatever track is first.

So such a warning color would need to verify that the OPTIONS are identical between multiple adds of the same track, but those options aren't finalized (you can change them) until you start the encode.

I'm not on the development team, but I'd say this falls under, "Patches welcome".

Perhaps not as an error but perhaps just some kind of indicator. Say highlight areas where the source track is used more than once with some color indication (perhaps yellow or dark gray just to indicate them). Depending on how context can be obtained, perhaps the indicators need only show when one of the duplicate tracks is being adjusted (has a focused element). If it's intentional, the user keeps going, if it's not then showing the dupe then can at least make the user aware of it in case it was a mistake.