Hmm. It shouldn't be that tricky. In my test, I made sure that the smart "Star" tool was selected, and when I expand the take lanes, and moved the cursor over the clips, it changes to the I-bar + stacked clip icon.
I'm not sure what else to try... when all else fails, save and close the project, close and re-open SONAR, and open the project again ... and see if it works.
Are these audio or MIDI clips? I'm testing with audio. I don't know why that would make a difference...