Spin the event loop to process the paste operation completely.

Manually when copy and paste done on combo it works as expected. But
while calling copy and paste API on combo there is an inconsistency. It
is due to pending UI events before we check text on combo.

see #2485

Author: raghucssit

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Combo.java

@@ -34,6 +34,7 @@
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Combo;
+import org.eclipse.swt.widgets.Display;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -236,6 +237,11 @@ public void test_copy() {
 	combo.copy();
 	combo.setSelection(new Point(0,0));
 	combo.paste();
+	// Spin the event loop to let GTK process the clipboard + entry update
+	Display display = combo.getDisplay();
+	while (display.readAndDispatch()) {
+	    // loop until no more events
+	}
 	assertEquals("23123456", combo.getText());
 }
 
@@ -501,6 +507,11 @@ public void test_paste() {
 	combo.cut();
 	assertEquals("1456", combo.getText());
 	combo.paste();
+	// Spin the event loop to let GTK process the clipboard + entry update
+	Display display = combo.getDisplay();
+	while (display.readAndDispatch()) {
+	    // loop until no more events
+	}
 	assertEquals("123456", combo.getText());
 }