I've downloaded OpenCascade V3.1 and V4.0 for Linux.
With both versions there is a problem with the demo application AISViewer, TTOPOLOGY etc:
The menu window created (File, View, etc) at program start seems do be inactive since no menu item can be selected nor the window is refreshed, when it has been minimzed.
The application together with demo.tcl scripts works well, only this menu windows fails to work as expected.
I am using Redhat Linux 7.0 with Tcl/Tk 8.3