Question

Can graying out of controls be done through your program (similar to the mode_tile when set to 1 function)?

Answer

You can set any control to be grayed at run time, by setting it's Enabled property and further making them invisible by setting it's Visible property.

(defun c:DclForm1_Button_Clicked ()
; disable / grey out the text box 1
(Odcl_Control_SetProperty TestProject_DclForm1_TextBox1 "Enabled" 0)
; re-enable the text box 2
(Odcl_Control_SetProperty TestProject_DclForm1_TextBox2 "Enabled" T)
)