Describe the bug
On IE11, gallery captions appear below the image, rather than on top of it. They're also hidden by the "Upload an image" drop zone. In the deselected state, the captions are pushed out far to the right of where they're supposed to be.
To Reproduce
Animated GIF

Tested in:
Windows 7, IE 11.0.9600.17420
Gutenberg 3.4
This could be fixed by applying actual left/right and bottom position for the figcaption absolute positioning styles. So, basically adding this:
figcaption {
position: absolute;
left: 0;
bottom: 0;
...
I didn't go ahead and created a pull request fixing this as I'm not really sure why there is this flebox set for the gallery figure... So, can anybody explain it? What's the purpose of it? What was the desired layout?
If the flexbox from figure is removed, you can even omit the left: 0; styles above.
This PR is fixed by #9762.
Thanks again for the advice here.
Closed via #9762.