I really dont know what the idea behind this fake button but even if you are using it as "fake popup" it is broken. you need to click to open and then click to close. If you have it open and then scroll the page the "popup" doesnt stick with the item and if you scroll above the subnav then the "popup" scrolls on top of it.
Personally I dont see a purpose for it
Just to make sure we're talking about the same thing here:
The purpose is, well, to provide additional information about an issue that is not visible in the list view (like the comment count which is a bit expensive..)
Currently there is not much to see and it's fairly unusable (the display and scroll issues you mentioned), but an AJAX call is made to the server and, in theory, this "popover" could display a bunch of additional information, graphs etc.
Maybe we should deactivate it until it's usable ?
If its a popover then it should look like a popover and not a button that you turn on and off
How does popovers looks like?
So I've deactivated and @todoed it for now. Maybe we can explore this later.
Is this button (view mode) is really needed thing BTW? May be we can left HELP mode constantly?