you have parameters that use nk_bool, like for the nk_input_button, however you are handling those as int's instead... and in some places even comparing against "true" if (down==1 && ...) ... which is a bug and should be if (down && ...) (for the click on button release) and similar logic for the dragging of move/size)

so passing anything but 1 to that to cause those to fail.