Change clip to Drop Frame for multigroup

Hi everyone. I'm having trouble creating a multigroup.

1 set of clips has been ingested using Non Drop Frame, and when I try to multigroup I'm getting the mixed DF NDF error.

I tried changing the master clip to DF by changing the colon to semi-colon in the start time, but it doesn't seem to want to change.  

Does anyone know what I"m doing wrong?

Thanks,

Brad

Media Composer 7.0.6