Vector plots and persistence in X-Y mode

[sharpie7]

Thanks for producing such valuable improvements to the original software. I am always so disappointed when simple limitations on software hold-back good devices and you're doing a great job avoiding that for the VDS1022.

Anyway, a couple of requests: I use X-Y mode to view the output of my curve-tracer, but even with the improvements you've already made there are a couple of limitations on X-Y mode that would be nice to fix:

• The X-Y mode always displays in dots even if "Vector" is selected in the display options. It would be really good to have the option of vectors for X-Y mode.
• There is no persistence support in X-Y mode. That might also be useful.