I was somehow able to show the toolbar using a context menu. Now that's shown, I cannot hide it again, and I cannot configure it except for basic functions, such as whether to show text or not. Ideally, the user could configure which buttons go there, add expanding spacers or separators, and have all the usual toolbar configuration options. The settings menu should show an option to show/hide and configure the toolbar.
Right-click on the menu bar.
Thanks. Enabling the toolbar is not persistent on quitting the application. Is that intended?
Officially, KCalc has no toolbar. The fact that you can accidentally enable it using right-click on the menu bar needs to be investigated and fixed.