Hi Tom,

I'm running v 4.33a ran into a case where

the program was very unresponsive.  In debug mode it showed that the opengl screen and  VRML parser were constantly updating.  It came down to this line in the function void CGViewDlg::ChangeToolPosition();

if (GetToolFileToDisplay(&UsingDefault) != m_ToolFileDisplayed || m_SceneIsDirty)

{

..

}

I didn't dig into it too deep, but what was happening here was one tool path had a lower case 'c:\" the other had an upper case  "C:\".  I'm not sure why this was but this change makes the code more robust.

if (GetToolFileToDisplay(&UsingDefault).CompareNoCase(m_ToolFileDisplayed) || m_SceneIsDirty)

{

...

}

This also occurs in the CPreviewFileDialog.cpp file.