+ int width = get_width();
+
+ if (Keyboard::modifier_state_contains (ev->state, Keyboard::TertiaryModifier)) {
+ /* handled by button release */
+ return true;
+ }
+
+ if (ev->y < 20) {
+
+ /* upper section: adjusts position, constrained by width */
+
+ const double w = fabs (width_control->get_value ());
+ const double max_pos = 1.0 - (w/2.0);
+ const double min_pos = w/2.0;
+
+ if (ev->x <= width/3) {
+ /* left side dbl click */
+ if (Keyboard::modifier_state_contains (ev->state, Keyboard::SecondaryModifier)) {
+ /* 2ndary-double click on left, collapse to hard left */
+ width_control->set_value (0);
+ position_control->set_value (0);
+ } else {
+ position_control->set_value (min_pos);
+ }
+ } else if (ev->x > 2*width/3) {
+ if (Keyboard::modifier_state_contains (ev->state, Keyboard::SecondaryModifier)) {
+ /* 2ndary-double click on right, collapse to hard right */
+ width_control->set_value (0);
+ position_control->set_value (1.0);
+ } else {
+ position_control->set_value (max_pos);
+ }
+ } else {
+ position_control->set_value (0.5);
+ }
+