Version: (using KDE 4.2.2) OS: Linux Installed from: Ubuntu Packages As it it is say in the title, even if the icon is selected to appear in the kmail_part: principal_toolbar, the icon doesn't appear. I will try to add an image in order to show this more explicitely.
Created attachment 33149 [details] Illustration of the icon missing
do you get the same result if you rename the kontactrc file ? (in .kde/share/config)
I have just try to move kontactrc, and I have exactly the same result.
New fact: the icon has reappear as I have delete the list of dynamic actions (I didn't have create it, and I don't where they are coming from).
*** This bug has been marked as a duplicate of bug 192816 ***