If I select some text by dragging the mouse cursor over it, it gets highlighted as it should; but if I then bring up the context menu, the highlighting vanishes (not a problem in itself), and it's as if I hadn't selected anything. "Cut" and "Copy" are greyed out in the menu. I think it has something to do with mouse buttons. To drag the cursor and select, I have to press on the mouse pad (like pressing the left button); and to bring up the content menu, I have to hold down the command key and press again. It's normally control + press that brings up such menus, but with RSyntaxEditPanel I have to use command + press.
If I change in mouseReleased in RTextAreaMutableCaretEvent in RTextArea to use MouseEvent.BUTTON1_MASK instead of MouseEvent.BUTTON3_MASK, the menu comes up whenever I do the equivalent of left click, which is what I have to do to move the caret using the mouse. There's probably some way to make the menu come up with control+press, which might work, but I don't know what it is.
Also, if I select some text as above, copy it with command-C (this works), and try to paste it using command-V, I have to do command-V twice to make the pasted text appear. It looks like the first command-V doesn't have to be a command-V; moving the mose cursor and clicking to set its position will also work -- and that will often be what someone does when cutting and pasting.
I don't know how to tell what the version number is, but I downloaded from git today.