Comment 2 for bug 24033

The mouse settings for single-click and double-click only affects the selection and opening of files and folders. It doesn't affect other system mouse clicks, like menus and icons on toolbars. System Settings is like that, and many other KDE apps behave this way too, like KControl (the original KDE Control Center). System Settings is not a Konqueror folder full of icons, therefore it doesn't behave like folders and files in Konqueror.

Thank you for the suggestion. If there are plans to change this behavior, the bug will be reopened.