QTextEdit/QLineEdit and special character composition does not work correctly

Also applies to snow leopard, and Qt 4.6 branch.

When you compose an accented character (such as the key combo 'e to create é) in a QTextEdit or QLineEdit (other widgets also suspected), it displays the character correctly, but it actually inserts 2 characters: the newly composed accented one, and the second keypress, so for 'e the widget will contain "ée". The second "e" is not immediately visible (though it exists if you ask for the widget contents) but appears as soon as you type some more text.

This is a pretty plain configured 4.6, i.e. using Carbon. You can reproduce this easily even with for example Qt Assistant, just go to the search textentry or the index textentry, and type `ex, which should give you "éx" but actually gives you "éex" (i.e. the middle character "e" should not be there). Similarly 'ax should give áx but gives áax, etc.

This problem does not exist on 4.7 (git) built with Cocoa. I have not tried building 4.6 with Cocoa.