As audiobblog mentioned. Select needed posts -> at the bottom there are buttons to "Add more topics / templates" or "Replace topics / templates" (hover with mouse for tool-tips if needed).
Kill the Firefox via task manager or restart the PC. After that make sure to use 4.53 final. It's not using Firefox anymore at all. You just have old instances.
It will be the same with Chrome in final version (it only affects sites using Cloudflare, just few). That's the only way at the moment. I have mentioned that here: http://poster.themasoftware.com/faq.php?expand=faq507
You can disable forums checking in background in "CONFIG" -> "Other" -> "Check forums in background for domain changes" (I have actually improved for final version to skip those sites when that option is enabled, it won't open Chrome then).