[bug] crash when touching/clicking many times

I unfortunately noticed that too many clicks on a canvas/sketchpad may cause Opensesame to crash.
a simple example:

# Generated by OpenSesame 2.9.6 (Hesitant Heisenberg)
# Sun Jun 21 00:15:46 2015 (nt)
# 

set background "black"
set canvas_backend "xpyriment"
set compensation "0"
set coordinates "relative"
set description "Default description"
set foreground "white"
set height "768"
set keyboard_backend "legacy"
set mouse_backend "xpyriment"
set sampler_backend "legacy"
set start "experiment"
set subject_nr "0"
set subject_parity "even"
set synth_backend "legacy"
set title "New experiment"
set width "1024"

define sequence experiment
    run getting_started "always"
    run welcome "always"
    run loop "always"

define notepad getting_started
    set description "Some pointers to help you get started!"
    __note__
    Hi,
    Welcome to OpenSesame 2.9.6 "Hesitant Heisenberg"!
    If you are new to OpenSesame, you may wish to follow one of the tutorials,
    which can be found online. There are also many example experiments, which will
    help you to get started with creating your own. These can be found in the
    "examples" folder provided with OpenSesame or, again, online.
    For more information, please refer to OpenSesame documentation area:
    - 
    And feel free to ask for help on the forum:
    - 
    Have fun with OpenSesame!
    --
    Sebastiaan
    __end__

define loop loop
    set break_if "never"
    set column_order ""
    set cycles "5"
    set item "sequence"
    set order "random"
    set repeat "1"
    run sequence

define sequence sequence
    run welcome "always"

define sketchpad welcome
    set description "Displays stimuli"
    set duration "10000"
    set reset_variables "no"
    set start_response_interval "no"
    draw textline 0 0 "OpenSesame 2.9.6 Hesitant Heisenberg" center=1 color="white" font_family="serif" font_size=32 font_bold="no" font_italic="no" html="yes" z_index=0 show_if="always"

if you touch many time opensesame crashes; probably during the repetition of the trial (which on my tablet maybe takes much more time than a PC)

this is bad since I'm going to leave the tablet unattended during my experiment