Gary,
At the base of your joystick is a device to lock the joystick and make it inoperative. Early tractors, such as my 1998 4200 had a simple sliding lock pin. The joystick was either locked or unlocked. Sometime between 1998 and 2000, the lock was changed to a vertically travelling lever with three notches to secure it. When the lever is in the bottom position the joystick is locked. When it is in the middle position the joystick is unlocked but the regenerative function of curl circuit is locked out. When the lever is in the top position, the joystick is fully functional, including the regenerative function of the curl circuit.
Attached is an illustration from the on line manual showing the newer, three position locking control.
Selective Control Valve (SCV) lock lever (A) allows the operator to control the type of SCV lever movement needed for a particular operation or situation. Operation of the lock lever is indicated on label (B).
Move lock lever to the top position (C) to allow SCV lever movement in all directions. Operation of the SCV is totally unlocked.
Move lock lever to the middle position (D) to prohibit engagement of the REGEN (regeneration) function of the SCV. This position is recommended for all attachments except for the front loader. Loader operation may benefit from the use of the REGEN function. The REGEN position is available only with lock lever in position C.
Move lock lever to the bottom position (E) to prohibit SCV lever movement in all directions. Operation of the SCV is totally locked.