What can Omni Menu do that I cannot do through Setup >> Company >> Palettes?
Discounting that fact that the Omni Menu user interface is much more powerful and easier to use,  Omni Menu will allow the editing of the Great Plains Toolbar and will allow the editing of palettes from Third party products (as long as they follow the standards).  Omni Menu can display nested palettes (ie. a palette which opens another palette) in its "By Toolbar" view.

How can I add a window from System Series to a Palette or Toolbar?
Unlike the standard Great Plains palette editor, Omni Menu can be used to add a window belonging to the System Series to any palette or toolbar.

What standards must a Third party developer follow for their palettes to work with Omni Menu?
For Omni Menu to be able to edit a Third party palette it must be able to identify the palette form from the Palette series in the Third party dictionary, and find the palette entries in the SY_Palette_MSTR table.

How do I get a Third Party palette to work if they have followed the standards?
You must find the existing Third party palette entries under By Dictionary >> Great Plains main product.  They will be shown as Unknown palettes.  You can then use the Attach button to associate these palette entries with the actual Third Party palette's form.

Why must I Attach a Third Party palette?
Due to a additional Product ID field not be in the SY_Palette_MSTR table, it is not possible to identify automatically which entries in the table are associated with which Third Party palette form.  You can create this relationship in Omni Menu using the Attach feature.  Once the association is created it is used by Omni Menu and Omni Security to access the palette via the "By Toolbar" view.

All my Third Party palettes show the same entries, why?
You have not attached the palettes and so all your palettes are being entered with the same Palette ID of 0.  You must Attach the Third Party palettes to show the existing entries and not add the entries again manually.