I usually use Item / Mark items, then Item / Add marked items as children to assign an additional parent.

 

I thought it would be nice to try the alternative, control and click and drag. Doesn't work for me - whenever I try it, IQ tries to draw a net around multiple items. Also, very annoyingly, I was trying to click and drag an item in my Appointments grid elsewhere. My finger slipped off the control key, and the item in the appointment was moved rather than copied. Result: it fell out of the calendar, and the Where and the Description for the appointment were lost.

 

Comments / help for the idiotic (me!) would be appreciated.