It seems you can't "+Interesting" a tag if you already have an interesting tag thats starts with the target tag.
For example, if you have "asp.net-mvc-2" as an existing tag the system won't let you add "asp.net" later. It only shows the option to remove, but it doesn't exist in the interesting list. Same with sql-server and sql. You have to delete the longer interesting tag and add them from shortest to longest. Wouldn't be such a big deal if the shorter tags were highlighted as interesting if the longer tag existed, but they aren't.
I did some digging and found the source of the bug... there is a corresponding problem in the ignored tags code:
if ($("#interestingTags").text().indexOf(h) > -1)
If the target tag exists in any form in the combined text you can't add it. A simple fix could be:
if ($("#interestingTags").text().indexOf(' ' + h + ' ') > -1)
This way it would have to be an exact match. I find it strange I'm the first person to run in to this
Just realized the code above might not work on the first or last tag in the list. Here's a better version:
if (' ' + $("#interestingTags").text() + ' '.indexOf(' ' + h + ' ') > -1)
This has to be the most meta post ever: Finding a bug. Fixing it. Fixing the fix. Then having to post a bounty on the "question" so it doesn't get lost in the noise.
Kind of sad this only got as many votes as my only other post on meta which was a three word joke.