When going into Tools-> Configure Toolbar's there was option in past krita version (2.9 i think), to use only action icon for button. But right now this option is gone - you can add only text buttons or text with icon. Only icon - option is missing.
Hi @bartosz.styperek, You are right, this is a regression I confirm done between 2.x to 3.x series. The previous Tools-> Configure Toolbar had two buttons: - Change icon - Change text ( ref: @DmitryK's blog: http://3.bp.blogspot.com/-tmyFCaUWboE/U4xgxB3PSvI/AAAAAAAABk0/_4V7SjDPc-A/s1600/krita-tool-bars.png , june 2014 during http://dimula73.blogspot.com/2014/06/some-notes-from-krita-sprint-2014.html )
I made a workaround to only show icons for actions that do have an icon (and remove the empty icon space when they don't have an icon) So, if someone uses an action in the toolbar which doesn't have an icon, please file a bug report for this icon and assign it to me.