Trying to copy entities with reference to clipboard from sheet tab to paste into another sheet or another drawing file.

When in sheet tabs, entity selection always fails (unspecified error) but this works when selecting from the model tab.  Obviously there is some difference in this Ctrl+Shift+C command between model tab and sheet tabs.  Is this a "feature" (bug), or is there a simple setting I can tweak to make it work in sheet tabs?

Using latest V1R3.

Thanks,

Jim