Problem with Read Mouse when also setting background colour

Actually if I have stimuli appear and disappear, before the images I am supposed to choose, then the function still acts odd.

I've adapted the stimuli to run how I want my experiment to look, and I'm getting strange variables - e.g. 3 when I click the right block, but 0 when I click the left block. I get the same problem also if I set the range to 3 4. Previously showing and clearing bitmaps seems to mess up the function.

Code I used to test this below:

&&&&&&&&

# in this task, 3 bitmaps are shown, and participant needs to select one


options
mouse on
background color 128 128 128

fonts
arial 20

task click
show text "gggg"
delay 1000
clear -1
show text "aaaa"
delay 1000
clear -1
draw off
show rectangle 165 0 140 32 30 30 30 #5
show rectangle 15 0 140 32 30 30 30 #6
draw on
readmouse l 1 5000 range 3 4
set $number_of_bitmap bitmap-under-mouse MOUSE_X MOUSE_Y
show text $number_of_bitmap 200 200
delay 500
clear screen
delay 500
save RT $number_of_bitmap

block test
tasklist
click 10
end