// un evenement de la souris quelconque
if(event.EventType == EET_MOUSE_INPUT_EVENT )

//Si il s'agit d'un appui
if(event.MouseInput.Event== EMIE_LMOUSE_PRESSED_DOWN)

//Si il d'un relachement du clique
if (event.MouseInput.Event == EMIE_LMOUSE_LEFT_UP )


Etc

Enumeration values:
EMIE_LMOUSE_PRESSED_DOWN Left mouse button was pressed down.
EMIE_RMOUSE_PRESSED_DOWN Right mouse button was pressed down.
EMIE_MMOUSE_PRESSED_DOWN Middle mouse button was pressed down.
EMIE_LMOUSE_LEFT_UP Left mouse button was left up.
EMIE_RMOUSE_LEFT_UP Right mouse button was left up.
EMIE_MMOUSE_LEFT_UP Middle mouse button was left up.
EMIE_MOUSE_MOVED The mouse cursor changed its position.
EMIE_MOUSE_WHEEL The mouse wheel was moved. Use Wheel value in event data to find out in what direction and how fast.
EMIE_COUNT No real event. Just for convenience to get number of events