1) Start print from SD card (using "Print from SD card" on Machine control panel). Close Simplify 3D. This aborts the SD card print. Could be by design, to stop people leaving heaters on or something, but it needs a "Should I mess up your print yes/no?" dialog.
2) "Print from SD card" option doesn't show either the long or short file names.
My SD card currently has one file called "1.GCODE". This is what I see. BTW, the 1 at the start is just luck, if it were called 2.GCODE, it may still show 1***.