Enable CKEditor toolbar button only with valid text selection?
问题 I'm working on a CKEditor plugin for annotating text and adding margin comments, but I'd like some of my custom toolbar buttons to be enabled only when the user has already selected a range of text. Whenever the user is typing, or the cursor is at a single-point (instead of a range), the buttons (and their associated commands) should be disabled. I'm a pretty experienced plugin author, and I've spent a fair amount of time hunting through the core API docs, but I haven't found anything yet