Elementor Wrong display on firefox

I discovered a very unpleasant Elementor display bug on firefox (on the desktop computer).  Everything works right in other browsers. 

1/ in a fresh wordpress install with only elementor installed, the row gap of the parent section (containers )doesn’t apply on tablet in the editor when set in percentage unit. It displays normally when set in pixels

But the most stunning is that this percentage  bug makes the widgets of the inner containers (title, text, button) simply vanish in firefox tablet view. the background image of the second container stays visible, but nothing in the second container with text and other widgets

2/ in another install, I had buggy containers in firefox (they don’t stack at all on tablet and mobile, no matter what I do (section direction set on vertical, wrap)  with huge spacings in the top area of the parent section ). 

I discovered while investigating, that these buggy sections in firefox, had all the gaps set in percentage. So I tried to set the row gap of these parent sections in pixelsz, and BAM ! everything instantly display normally in firefox.

There is a big mess with firefox when sections gaps are set in percentage on tablet. and in the last Elementor version on the fresh install, row gaps set in percentage do nothing on taglet and mobile in the editor, they simply don’t apply. and here also, the content of th the inner containers vanish on firefox only (tried on a section with 2 inner containers, one with background image, and the other with title , text, and button)