BCGControlBar Pro for MFC
virtual BOOL CBCGPToolbarButton::CanBeDropped ( CBCGPToolBar pToolbar)

Indicates whether a button can be dropped on a toolbar.

Nonzero if a button can be dropped on toolbars or menus during customization; otherwise 0.

By default, toolbar button can be dropped on every customizable (non-locked) toolbar.

Override this member function in a CBCGPToolbarButton - derived class and return FALSE, if you need to prevent this.

pToolbarSpecifies a destination toolbar.