For the past few weeks I've had this weird behaviour of minimised apps.
If I minimise an app with the yellow button, then it will go in the left side of the dock, like this.
Now if I try to maximise it by clicking on the dock icon, in the previous image case the icon on the left, the app doesn't maximise. It shows that it is open, as the top bar shows the apps menus, but it doesn't show in the main view, as you can see in the following screenshot attached.
I'm really confused, as for some apps it does work, but for others it doesn't. It all started from WhatsApp, then I erased the dock.plist file and the problem went away, but now the Activity Manager has the problem. Any clues?
I know that there is a similar question to this one already, but there is not real fix to this problem there, just the suggestion not to use the minimise button.