Would be nice if someone can implement something like this in upcoming Plasma 5.20:
Some example of main issues We'll can have with popups is when there are so many wireless/VPNs or a lot of notifications to review. The use of scrollbars in small popups is improductive and annoying.
Almost all of this is already possible right now. :) Have you tried adding a wide right edge panel (optionally auto-hiding) and adding these widgets to it? It mostly works quite well. In cases where it doesn't (e.g. the search widget doesn't display the search field), those are simple bugs that we can and should fix, for which I would request bug reports at https://bugs/kde.org. Thanks!
A right panel is not a solution. Notification area continues to show a popup, not an embeded widget in panel. I tried to resize it, but without success. There are a hack to do this, but it's not recommended because it is not official and it potentially conflicts with next plasma versions changes:
Full Height Plasma Systray Popup
Update: attached a little patch that works for me:
I just tried setting the popup height to max...
In order to enable or disable the WiFi I need to move the mouse from the bottom to the top, and to switch categories the same again.
It makes quick operations take more time. There's also the problem of how to put the side bar:
If the panel is on the left or right then putting it right next to the panel looks weird and putting it on the opposite side destroys usability.
So, I don't think this is too much of a good idea. At the very least it's quite a bit of work to make it look good and still be usable.
Btw: if you make the panel big enough then the notifications widget does work like you'd expect it to. I just tried in 5.19.3
I think the bigger side panel instead of the popup is more usable and productive if you have to manage multiple VPN connections, have a lot of notifications and have a good amount of data saved on clipboard. But I'm agreeded with you that sometimes it compromisse usability.
It's necessary some studies and some bit of work to make it looks good and still functional, as you said. If I can get some time I'll try to design a mockup for it.
Currently my setup with plasma 5.19.2:
