because I need to keep always open the left side panel to see which applications are currently running and to switch between them: its quite unfriendly and space expensive.
I just want to make sure you are aware that the appearance of that "space expensive" left hand size is configurable. If you resize your browser window and make it smaller, if the width of the browser window drops below a certain amount, 1400 pixels, then that left hand side disappears. That number 1400 is configurable and if so if you set it to a higher extreme amount then the left hand side never appears unless you click the icon to make it slide out (or have an extremely large monitor). You can follow these instructions here
http://4js.com/online_documentation/fjs-gas-manual-html/#t_gwc_js_custom_sidebar.html and change the number to a higher amount. As some people discovered there is a .css you can edit directly if you want to avoid the whole grunt process and don't do any other customisation. To find the .css, search for 1400 in .css files beneath FGLASDIR/web :-).
I like setting the 1400 to a much larger number so that the navigation panel never appears unless you explicitly click on it. If you think about it, this left hand panel is analogous to what used to happen with the GDC when you click on the GDC taskbar entry in the windows taskbar. This would show all the windows and applications available and you could select and bring a different window to the top.
So whilst I personally don't live having that left hand panel visible by default and taking up space unnecessary, by simple configuration steps I can make it disappear except for when I want to actually use it , and I accept that by relating it to GDC on Windows and noting that the UX is similar.
The other thing to be aware of, is that in the latest release of the GWC-JS (1.00.30) a new style was introduced so that you could control if each new program remained in the same browser tab, or if each one opened in its own browser tab. Have a look at
http://4js.com/online_documentation/fjs-gas-manual-html/#gas_whatsnew_300_mr.html and search for browserMultiPage. This isn't quite the same as appearing in one browser tab with a rendered tab for each program but might be acceptable.
Finally the best time to have these types of discussions about new functionality is during the Early Access Programs that occur prior to each major versions release. So in the case of 3.0 which was released December 2015, the Early Access Program (EAP) ran during the last quarter of 2015. The EAP for 3.1 isn't far away, I don't have the exact dates but I would expect some posts to go out soon giving notice. (support team members got their first look this week).
The browserMultiPage style was introduced as the result of customer feedback halfway through last year but we would rather have got that feedback during the 3.0 EAP, rather than having to do that implementation mid release cycle.
I see looking through the old eap mailing lists you participarted in previous EAP's but not the 3.0 EAP. I would strongly encourage you to participate in the upcoming EAP and make sure that the GWC-JS is an acceptable path forward for those with StartMenu & TopMenu tabbed container model. You can give feedback now if the configuration step above doesn't help, but you are probably looking at a 3.1 implementation if there is any change seen we are so close.
Reuben