Hi,
Months ago, I solved this problem on another PC, but have forgotten what was the relevant setting.
If I click F2, the php application shows up in the browser, and runs correctly.
But if I set a breakpoint, then run it from the PHP debug menu, WeBuilder 2016 brings up an Untitled#.htm file in the editor, instead of creating a tab in Chrome, and then stopping at the breakpoint.
Again, this works on another computer, but I don't remember how this was solved.
The PHP location setting in Options, is C:\php563xd\php.exe. This was installed from http://www.blumentals.net/lv/download-php.php, same as the other PC.