Many of you are still resisting ribbons, but for those of you that aren't, you may have observed some quirky behavior. Or possibly, you've gone into the CUI editor and changed some things you didn't intend to change?
I am running AutoCAD MEP 2011 and have noticed a few cases where I opened DuctDesigner 3D® or PipeDesigner 3D® and certain tabs are missing on the ribbon toolbar. There are a number of possible causes for this, but who cares.....I just want my ribbons back right? No need to worry as our R&D department has two hidden commands in our CAD products to help you out, but be sure that you really want to rebuild your QP CAD ribbons before you run the commands.

In DuctDesigner 3D®, run the following command: QPENDREBUILDCUI
In PipeDesigner 3D®, run the following command: QPEN_REBUILDCUI