I haven't seen many one button mouse lately but in the ENVI classic help, it does discuss the expected key combinations: Note: On Macintosh platforms, where only one mouse button is available, use Alt/Option+click to emulate a middle mouse button. To emulate a left mouse button, use Apple/Command+click. Do these work for you?

Thanks Mari. No, the emulation doesn't work. I also just tried an Apple 'magic' mouse, with the emulation keys and no joy. I suspect there's something wrong with the Logitech 3-button mouse driver that won't let me emulate the right button in their setup.

Hello, I requested help in early May and got a response from Mari Minari. I answered that her suggestions didn't work and have heard nothing since. I just tried to initiate a new request, but can't get that to work. I've tried various keys to emulate a 3 button mouse. I've also disabled the Logitech driver, but no change. The lack of a 3-button mouse, which is required to work with HDF5 files, makes ENVI 5.3 useless to me. Please help.

Does your 3-button mouse work with your OS outside of ENVI? If not, then this is an OS issue and I would work on getting the 3 button mouse to work via driver updates or a new mouse. It is much easier working with a 3 button mouse in ENVI and I am not completely sure the single mouse button emulation works in the new interface. It might in ENVI Classic.

Well, it seems my computer 'healed' itself: The right button works now! I don't know what I did, but I'm still using the Logitech driver and told it to emulate a right button, which it does well in other applications. Now it also works in ENVI! Thanks for the suggestions, Tom Farr, JPL