Disable LXDM and Start GTK Application

I try to start the Xserver manually after disabling the LXDM desktop.

After start up the ps ax | grep X shows me:
[upload|Kma+19V4x7FDKb5aEzttt8QPGU0=]

And after stopping the lxdm
[upload|xu3UxnniN/u6Uy7YmIIyrZi0KVs=]

When i try to start my GTK applikation, it fails because of “cannot open display: 0.0”
[upload|xLMP2+VB1HUeFTmMAPKP8j1hOLA=]

Then i tried to start the XServer like this, without any success. The login screen appears in the terminal.
[upload|bw5PmC/V+zQgOCxMvikqxsqCfZY=]

Does anyone have an idea how to correctly start the display driver for a customer application?
Many thanks for hints and helping me with this issue.

Please have a look at our X Window Simple App which does exactly what you are looking for:

http://git.toradex.com/cgit/meta-toradex-demos.git/tree/recipes-graphics/x-window-simple-app?h=rocko