hello im having problem with my tileset not able to be destroy because i draw the pixel. Is there a better way to do it?

this is for the create event

//createblock
global.ground_tilemap_grass=layer_tilemap_create("tilt_wall",0,0,til_wallgrass,room_width,room_height);


this is for the keyboard press

var tilemap_id = layer_tilemap_get_id("wall") {
tilemap_set_at_pixel(global.ground_tilemap_grass,0,mouse_x,mouse_y)
{
layer_tilemap_destroy(tilemap_id);
}
}