Sure. If the MediaViewer is not handling any single piece of the code which is relevant to this task. It is always better to tag tasks with assumed tags to improve their discoverability, which in case they are not relevant can be removed anytime, but finding a task which is not tagged with proper tag is harder. Hence why I added certain tags.
Checked on desktop FF, Opera, Chrome, Safari. Checked on phone iOS 9 Safari, tablet simulator iOS 9 Safari, Android 5 Chrome, Android 5 Opera Mini (no compression), UC Browser (no compression), Windows Mobile 7.5 IEMobile on both orientations and LTR+RTL.
<noscript>/compression browsers were out of scope here.
Windows Mobile 7.5 IE continues to face problems of garbled rendering on RTL (not tofu, the blocks are scrambled), so that wasn't testable, but despite some pain with cert warnings the LTR MediaViewer showed the X button correctly.
Samsung Wave II (SamsungMobile) wasn't pulling up the MediaViewer properly on the beta cluster, but it worked fine on production. I have a hunch this won't be a problem on the stable channel, so can accept this risk for now.