I have the latest firmware on the device. Here another example:
When I create in eclipse a default android project and add a simple button within the LinearLayout with layout_width=fill_parent and layout_height=wrap_content everything works fine on my Archos 7 IT device. Even if I change the orientation the button still have the correct width.
In B4A I have created an empty project as well and I have added the following lines of code in the Activity_Create Sub:
myButton.Initialize("")
myButton.Text = "Click Me"
Activity.AddView(myButton,0,0,-1,-2)
myButton is a variable declared in globals sub
When I run the app on my Archos I have this bug with the screen orientation. First time, when I start the app the orientiation in landscape mode is correct and it looks like as in my eclipse project. The button width is 760 pixels. (800 pixels - 40 pixels for the softmenu on the right) When I change the orientation to portrait mode 40 pixels has been cutted of from the button width. (the softmenu is here on the bottom) Then, when I change the orientation back to landscape mode the button width is now 800 pixel (40 additional pixels) and the softmenu overlaps with the button.
Because the app made with eclipse does everything correct I don't think it is a device specific bug. It would be also interesting to know whether other archos 7 it users have the same problem. I would be glad if someone can help.