zoom: use the new pointer motion signal to move the zoom frame.
diff --git a/src/shell.c b/src/shell.c
index 9a9127b..cbb741a 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -3052,8 +3052,7 @@
 			else if (output->zoom.level > output->zoom.max_level)
 				output->zoom.level = output->zoom.max_level;
 			else if (!output->zoom.active) {
-				output->zoom.active = 1;
-				output->disable_planes++;
+				weston_output_activate_zoom(output);
 			}
 
 			output->zoom.spring_z.target = output->zoom.level;