Previously there was an option in the Edit Current Profile -> Tabs section to add buttons on each side of the tab bar to easily create and close tabs (one on each side). This option has disappeared since version 2.10 and is a regression in usability. Please put it back, a shortcut is not a replacement. Reproducible: Always
Try Konsole->Configure Settings->Tab Bar - non-profile options were moved to this central location
ehh Konsole->Configure Konsole->
Found it, thank you.