Kdevelop allows for split views (splitting the editor window horizontally or vertically) like known from Emacs and other editors. There are even shortcuts to create such splits (Ctrl+Shift+T, Ctrl+Shift+L), but I couldn't find any shortcut to close view. How to close the view in Kdevelop? I feel that this is rather stupid question, but I checked menus, shortcut list, context menu and see nothing about that...
The KDevelop editor is based on Kate, so you'd think that using the equivalent Kate command to close a view (Crtl+Shift+R) would work, but it doesn't seem to be implemented. Many of the Kate shortcuts are available to be assigned in the Configure Shortcuts dialog, but again, not close window.
The only canonical way to close the view is to close all the open files in it.
It's sub-optimal, but if you are desperate for a keyboard shortcut, Crtl+Shift+W will close all but your current document, which has the side effect of also removing any other views.
This might be a good candidate for a feature request.