Memory Game "matched" thumbnails not showing in FireFox
Title says it all. I am attaching 2 screenshots taken from this site's demo page at: https://h5p.org/memory-game that show the problem. Display is OK in Chrome and MS Edge browsers, but not as expected in FF.
BTW, in FireFox the text "A free HTML5-based memory game content type allowing authors etc." at the top of the memory cards is not even displayed. Most strange!
PS It is not clear if bug reports should be created in the H5P forums or attached as comments to an H5P activity.