Why will Corel Draw not allow two curve objects to be combined?

There are many reasons why you can't combine two curve objects, one of them as mentioned above is that one is a group (even if its a group of 1 object)

Others are;

• One is a clone or indeed a master
• a Symmettry object
• a symbol
• is locked or on a locked layer
• either the start or end object of a blend group
• has a dynamic dimension or callout attached
• is just plain broken, you might have to recreate it. Try copying the object to a new document and then back again.

Thanks for the list!  That really helps.  I think I can rule out the group issue as ungroup is not an option for this object.  The rest I am going to try to work thru.

Select the object and see what it says in Status Bar and Objects docker.
It might give you a clue.

Thanks for the pointer.... Might give someone a clue 8-).  The object in question is a single object of type curve.  I went thru comparing the troublesome object with ones that work the way I expect.  I can not see any significant difference.  Also, the object is not locked nor is the layer.  The object in question is composed of several curve objects that were combined in the past.  I was just just trying to add one more curve object.

Might also try selecting all the nodes and "reversing" them then combine

Would be a good idea to share the file with only the troublesome objects in it so we can investigate