I have a very similar issue: starting a new Debug starts a new Firefox window (even if I already had a running Firefox window) with default startup page.
Except for point 4 ("selecting System Default Browser(Firefox) will open a new tab in the current Firefox"): when I set Eclipse to use "System Default Browser" it still opens a new Firefox window with default startup page.
I'm not sure but it seems to have occurred when Firefox got it's v36.0 update.
I will try Chromium to see if it works (as Iced Stitch suggests).
Versions:
- Ubuntu v14.04.2
- Firefox v36.0
- Eclipse Luna Service Release 1 "Eclipse IDE for PHP Developers" (v4.4.1.20140925-1820)
- PDT Extensions v0.21.0.201407100921
Eclipse "Web Browser" settings:
(x) Use external web browser
External web browsers:
[ ] Default system web browser
[x] Firefox
"Firefox" web browser is defined as follows:
Location: /usr/bin/firefox
Parameters: