Pull request #1862: REPORT-34907 linux设计器-纸张背景-渐变色，右边的游标不能拖动

Merge in DESIGN/design from ~PENGDA/design:release/10.0 to release/10.0

* commit '0bf03a25b340587175652e0dd3d2add7dd5e7a56':
  REPORT-34907 linux设计器-纸张背景-渐变色，右边的游标不能拖动

designer-base/src/main/java/com/fr/design/style/background/gradient/GradientBar.java

@@ -11,6 +11,7 @@ import com.fr.design.style.color.ColorSelectDialog;
 import com.fr.design.style.color.ColorSelectable;
 import com.fr.stable.AssistUtils;
 
+import com.fr.stable.os.OperatingSystem;
 import javax.swing.JComponent;
 import javax.swing.event.ChangeEvent;
 import javax.swing.event.ChangeListener;
@@ -124,14 +125,20 @@ public class GradientBar extends JComponent implements UIObserver, ColorSelectab
     protected void addMouseDragListener() {
         this.addMouseMotionListener(new MouseAdapter() {
             public void mouseDragged(MouseEvent e) {
-
+                int oldIndex = index;
                 for (int i = 0; i < list.size(); i++) {
                     if (list.get(i).contains(e.getX(), e.getY())) {
                         index = i;
                         break;
                     }
                 }
-
+                if(OperatingSystem.isLinux() && AssistUtils.equals(oldIndex,index)){
+                    if(Math.abs(p1.getX() - e.getX()) > Math.abs(p2.getX() - e.getX())){
+                        index = 1;
+                    }else{
+                        index = 0;
+                    }
+                }
                 boolean x = e.getX() <= max && e.getX() >= min;
                 if (x && e.getY() < MAX_VERTICAL) {
                     list.get(index).setX(e.getX());