Hello Seecah & Ayumi,
Many thanks for your help. (the anti-thick pills seemed to have worked, somewhat)
Below is my code (in lite_c) in case it helps anyone else.
(there have been 88 'hits' to date, so someone's interested!)

I did'nt want to get involved with panels, just wanted to use a simple bit-map which went invisible when 'clicked'.

BMAP* key_map = "key1map2.bmp";


function pickup()
{
if(event_type = EVENT_CLICK);
{
..... //switches key for 'key' mouse map
....
...
ptr_remove(key_map);
}}

action key //apply to key bit map(on floor in my case)
{
key_map = my;
key_map.flag = SHOW | OVERLAY;
my.emask | ENABLE_CLICK;
my.event = pickup;
}

This works just fine,
again, thanks for help, David