Well ... following your suggestion I uninstalled Start11, rebooted, and then installed a freshly downloaded (via My Account : Downloads) copy of v. 1.2. Clicking the About tab in configuration confirms that it is v.1.2.
When installation was complete, the System Tray appeared as normal. When I clicked yes to the prompt asking if I wanted to let Start11 enhance the taskbar, the System Tray disappeared. When I turned off Taskbar Enhancement, the System Tray came back.
Please let me know if I can provide any additional info that will help.
It came back instantly or after an explorer restart?
That is a curious issue as thats the first case we have encountered.
A few questions :
1) How many monitors do you have
2) Do you have anything else running which might impact the taskbar?
3) What scaling factor is your screen set to?
4) Is this a touch aware device?