[GEF] Slow the rate at which the AutoexposeHelper is polled to reduce…

… CPU usage

- See eclipse/gef-classic#492

org.eclipse.gef/src/org/eclipse/gef/tools/TargetingTool.java

@@ -13,17 +13,15 @@
 import java.util.Collection;
 import java.util.Collections;
 
-import org.eclipse.swt.widgets.Display;
-
 import org.eclipse.draw2d.geometry.Point;
-
 import org.eclipse.gef.AutoexposeHelper;
 import org.eclipse.gef.EditPart;
 import org.eclipse.gef.EditPartViewer;
 import org.eclipse.gef.Request;
 import org.eclipse.gef.commands.Command;
 import org.eclipse.gef.commands.UnexecutableCommand;
 import org.eclipse.gef.requests.TargetRequest;
+import org.eclipse.swt.widgets.Display;
 
 /**
  * The base implementation for tools which perform targeting of editparts.
@@ -93,7 +91,11 @@ protected void doAutoexpose() {
             return;
         if (exposeHelper.step(getLocation())) {
             handleAutoexpose();
-            Display.getCurrent().asyncExec(new QueuedAutoexpose());
+            // Reduce the rate at which the AutoexposeHelper is polled to reduce CPU usage.
+            // A value of 1 or 2 ms is enough.
+            // See https://github.com/eclipse/gef-classic/issues/492
+            Display.getCurrent().timerExec(1, new QueuedAutoexpose());
+            //Display.getCurrent().asyncExec(new QueuedAutoexpose());
         } else
             setAutoexposeHelper(null);
     }