"check out", "continue" or "read only"?? issues with each option

I want to "mock up an idea" and not save changes.. When I open the part/assembly and attempt to modify it, Windchill requires you select "check out", "continue" or "read only". Each of these options seem to have issues with what I am trying to do.

-If I choose read only, I cannot test the changes I want to test.

-If I check out the part, I am permanently modifying the part.

-If I choose continue, it lets me do whatever I want. I then test my changes and when I am done, I close files without saving. If I open the file a week later, and try to make a change.... Windchill now just lets me make the change without requiring the selection of "check out", "continue" or "read only"?? I would expect that it would discard the changes and reset the selection requirement.

It seems many assemblies just get in the permanent "continue" mode. Which causes issues.

For now, I check out - test my modifications - close without saving - and undo check out... not sure what issues that may cause???

Does anyone know of a way to "continue for current session only??