I find out how did I get the problem:
Start the PC without a TV at the HDMI output.
Plug in the HDMI cabel => as the TV is on, it did not send a information that he is online.
Change the Screen viewing to Advanced (both screens are able to use as one Dektop. => Die Fonts change.
Opera Windows get black.
To solve the problem check these Points:
Switch off/on the TV
Change the Graphiccard to intern/extern (as you have to cards like me ;)).
shot down the PC.
Start the PC with HDMI connection to TV (TV is on).
Wenn it is a Problem of Opera.
Regards Carsten