NSColorPanel is not a class.

[pjb@…]

NSWindow and a number of other Objective-C classes are mapped to symbols in the NS package in ccl::*lisp-classname-table*:

cl-user> (apropos "NS-WINDOW")
ns:+ns-window,  Value: #<objc:objc-metaclass ns:+ns-window (#x1D7D7A8)>
 ns:ns-window,  Value: #<objc:objc-class ns:ns-window (#x1D7D7D0)>
ns:+ns-window-controller,  Value: #<objc:objc-metaclass ns:+ns-window-controller (#x1D7D988)>
 ns:ns-window-controller,  Value: #<objc:objc-class ns:ns-window-controller (#x1D7D9B0)>
; No value
cl-user> (gethash "NSWindow" ccl::*lisp-classname-table*)
ns:ns-window
t

but not NSColorPanel:

cl-user> (apropos "NS-COLOR-PANEL")
 ns:ns-color-panel,  Value: #<objc:objc-class ns:ns-color-panel (#x1D73280)>
ns:+ns-color-panel,  Value: #<objc:objc-metaclass ns:+ns-color-panel (#x1D73258)>
; No value
cl-user> (gethash "NSColorPanel" ccl::*lisp-classname-table*)
"NS-COLOR-PANEL"
t

even after instantiating a NSColorPanel:

cl-user> (#/sharedColorPanel ns:ns-color-panel)
#<ns-color-panel <NSColorPanel: 0x31ae720> (#x31AE720)>
cl-user> (gethash "NSColorPanel" ccl::*lisp-classname-table*)
"NS-COLOR-PANEL"
t