On Wed, 27 Apr 2016, Guillaume Munch wrote:
This appears to be an issue on the latex side. Since you are using ERT, you will have to use one of the solutions from https://tex.stackexchange.com/questions/12262/multicol-and-figures by hand.
Guillaume, I tried both approaches on that stackexchange thread but could not learn how to add captions and labels to non-float graphic inserts. So, ... I went to the LyX wiki on Figures and found the answer: Insert the figure in a float and add the caption and cross-reference label to it. Then position the cursor immediately ahead of the float and invoke the Edit -> Float Settings checkbox. Deselect "Default settings" and select the "Here definitely" option. Set the figure width to 100% column width, save and compile. Hope this helps others, too, Rich