Toggling embedded GL View

Dear ROOT users and developers,

i am using ROOT 5.16.00 on a IA32 SLC 4 machine. I want to toggle an TRootEmbeddedCanvas between OpenGL view (using ->Draw("gl")) and the normal Pad view (using ->Draw("pad")), but toggling works only one way from pad->GL. Once the GL view is active there seems to be no way to get back. I tried clearing the canvas, deleting the Viewer3D but it did not help.

Calling the Draw("gl") Method without calling Draw() or Draw("pad") before also produces a crash.

Another topic is that to use the embedded GL view the user should either set gStyle->SetCanvasPreferGL(kTRUE) or set the name of the TRootEmbeddedCanvas to a string containing "gl" but only the first option seems to work.

I made a script "toggleGL.C" showing these problems. The application starts in "pad" view an can be switched to "gl", but not back.

Many thanks in advance for your help!

Boris