Hi Wolfgang,
I'm glad to see your progress!
There are no launchpad entries shown because launchpad could not obtain its configuration. Please try adding '/genode/launchpad.config' as boot module to your GRUB config. (in the snippet you posted, this file is missing) Btw, you can find a GRUB-legacy configuration file for the demo scenario at 'var/run/demo/boot/grub/menu.lst'. This file gets automatically generated by the run tool. How about using a verbatim copy of this file? As far as I know, GRUB-2 supports the loading of GRUB-legacy configuration files.
The dark line at the top of the screen is preserved for status information of the nitpicker GUI server. This is normal.
Is your mouse connected via PS/2? If not, the missing mouse cursor may be caused by the input driver, i.e., the USB driver. You could try replacing the PS/2 driver with the USB driver. Have a look at 'dde_linux/run/usb_hid.run' for an example of using the USB driver. I recommend to first test the changed 'demo.run' script on Qemu using the arguments found in the 'usb_hid.run' script. Once, you got it working in Qemu, you could give it a try on real hardware.
For testing, it is very helpful to have Genode's LOG output available, which is directed to the comport. Unfortunately, modern PCs don't have a comport anymore. However, on most Intel-based PCs, there exists a feature called AMT that allows for sending comport output over the network. If you are interested in exploring this, it is worthwhile to search for 'amtterm'.
Best regards Norman
PS: Your question about the Raspberry Pi is not forgotten. I just haven't found the time to try the current master branch on the Rpi yet. Please stay tuned! ;-)