Peter (and Frank),
Well I learned something new tonight. I had basically been using the same method as Peter had about using a different browser (that is, open the new browser, paste the url, etc).
So sure enough I search for the "open with" extension and eventually figure out that the extension is at the Thunderbird extension site. So step by step:
1. Go to "
https://addons.thunderbird.net/en-US/th ... /versions/ ". This is the "other versions" page because the current version apparently does not work in SeaMonkey.
2. At the bottom of the page download Version 6.8.6. (This appears to be the last version that will work with SeaMonkey and even though a version for SM 2.53.12 is not listed, the 2.49 version still works).
3. After downloading the file, go to the SeaMonkey "Add-ons Manager" under the "Tools" menu, and choose the Extensions tab.
4. Find the settings wheel near the top right corner, and click the small downward pointing triangle and choose "Install Add-on from file".
5. Find the downloaded file and install it. You will need to restart SeaMonkey after this.
6. After the restart the "Open with" extension pops up first thing so that the desired options can be chosen. The "Open with" extension seems to search for all installed browsers and then to list all the ones that it found. In my case I had to add five more.
7. Once all of the options have been selected, everything is set to be used, and the "Open with" option appears under the "View" menu if and/or when needed.
So in using this feature, when there is a web page that does not work correctly in SeaMonkey, while remaining on that web page simply click the "View" part of the menu bar and choose one of the "Open with" browser options that you have set up. Once you make that choice, the particular web page that you are having problems with will automatically open in the chosen alternative browser. No copying and pasting is necessary.
[Edit - 6-25-22: -- After reviewing what Frank said, actually you can just 'right click' on the problem web page and all of the "open with" options immediately appear. There is no need to even click the "View" part of the menu bar, as I wrote above. So yes, about "5 seconds" or however long it takes for the alternate browser to open.]
Nice little extension.
As always, thanks Frank.
v_v