You can view and edit Windows file associations via the Control Panel. In WinVista/7/8, you should find them here:
Control Panel » Default Programs » File Associations
Although it may be easier to just do this:
- Rename one of your TiddlyWikis from .html to .tw.
- Right-click on the file and choose "Open With »" from the context menu, then "Choose Default Program...".
- Make sure "Always use the selected program to open this type of file" is checked.
- Click "Browse" to locate and select the version of Firefox you want to use to open TiddlyWikis. (Be sure to select the firefox.exe executable.)
- Click "OK" to open the .tw.
- Now all your .TW files should open with your preferred version of Firefox.
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Once you asked the question, I liked the idea so much I stole it for myself. :) My browser of choice is Maxthon (
http://www.maxthon.com/), but, like Firefox, the current version isn't as TiddlyWiki-friendly as an older version I keep around just several old-school reasons (including TiddlyWiking). So I took my own advice and renamed a couple of TWs I keep on my desktop — my dream journal went from
dreams.html to
dreams.tw — so that I can quickly and easily open them in the older version of Maxthon, even though the newer version is my default browser.
I haven't done this with all my TiddlyWikis, though. Several of them are interlinked, and I don't want to invest the time in hunting down and updating the links just now. Plus, I occasionally share some of them and post them on the web, and I'm not convinced I'd want to rename them to .HTML files every time I do so.