http://bugs.winehq.org/show_bug.cgi?id=31291
--- Comment #12 from Rico kgbricola@web.de 2012-09-19 03:51:41 CDT --- to 3.) the input method using the super key, doesn't work for native apps and doesn't work for wine apps (because by default the key is assigned to something else)
However, if you use the "Compose-Key" - enabled in keyboard settings (also called "Multi-Key", I put it on the Win-Key, probably also called Super-Key), then the combination works in native apps (with en_US.utf8 and en_DK.utf8) and in wine using en_US.utf8. However it does not work when using en_DK.utf8 with wine. In the end the behavior is the same using the "Compose-Key" when using the "ä" directly. The difference is hitting "ä" doesn't show up any character while using "Compose-Key + " + a" shows '"a' in en_DK.utf8 wine.