The developer console has it’s client/server tabs initially right-aligned instead of left-aligned. If you cause the UI to get updated, it corrects itself. This happens both in studio and online.
Steps to Reproduce:
Open the Dev Console
Get the UI to be updated (i.e. swap categories, minimize/maximize the console, close/reopen the console)
Just a note that this was several months old bug. It always happens to me everytime but when I open the developer console, the client/server tab button immediately fixes itself after I opened the developer console.