Hi, I dont know why, but it seems there is no connection between FXGLViewer and ist target when FXGLViewer not is placed on window/mdi child directly following code works: -------- require 'fox' require 'fox/responder' require 'fox/glshapes' include Fox app=FXApp.new win=FXMainWindow.new(app,'title',nil,nil,DECOR_TITLE+DECOR_BORDER+DECOR_CLOSE,0,0,500,400); win.show mdi_client=FXMDIClient.new(win,LAYOUT_FILL_X+LAYOUT_FILL_Y) mdi_child=FXMDIChild.new(mdi_client,'mdi',nil,nil,MDI_NORMAL,30,30,300,300) mdi_client.setActiveChild(mdi_child) ID_QUERY_MODE = FXMainWindow::ID_LAST ID_GLVIEWER = ID_QUERY_MODE + 1 visual=FXGLVisual.new(app,VISUAL_DOUBLEBUFFER) #frame=FXVerticalFrame.new(mdi_child,FRAME_SUNKEN+FRAME_THICK+LAYOUT_FILL_X+LAYOUT_FILL_Y) | v viewer=FXGLViewer.new(mdi_child,visual,win,ID_GLVIEWER,LAYOUT_FILL_X+LAYOUT_FILL_Y) gr=FXGLGroup.new gr.append(FXGLCube.new(-1.1, 0.0, 0.0, 0.1, 0.1, 0.1)) viewer.scene=gr FXDial.new(mdi_client,mdi_client,FXGLViewer::ID_ROLL,FRAME_SUNKEN+FRAME_THICK+DIAL_CYCLIC+DIAL_HORIZONTAL+LAYOUT_FIX_WIDTH+LAYOUT_FIX_HEIGHT+LAYOUT_CENTER_Y,0,0,200,14) app.create app.run -------- but if You try to place viewer on FXVerticalFrame... whatever, the viewer loses its connection to its target Probably this is Fox problem so I should post it on Fox buglist or something...? TIA Marcin Mielzynski