Regressions with Internet Explorer: closed headings and hidden elements

[Jaifroid]

I have noticed two regressions:

• It is no longer possible to open or close Wikipedia section headings in IE11 by clicking them (this works in other browsers). I am referring to custom code in the app, not to the included JS (which IE11 cannot run);
• If the setting to show hidden elements is turned on, and headings are closed, some images in closed sections will be unhidden in IE11 (not in other browsers), leading to odd formatting.

Neither of these are critical, as they each have workarounds: for both of them it is enough to ensure that the "Open all sections" option is selected.

A fix for the first issue should be simple. The second issue is minor and not worth fixing given that the user can turn off display of hidden elements very easily (and it is off by default).