Pull request #1963: REPORT-30352 直接将RTextAreaBase的border的值改为0，以和8.0版本外观保持一致

Merge in DESIGN/design from ~YUAN.WANG/design:bugfix/10.0 to bugfix/10.0

* commit 'af1a3184ca257795f1acad72f411820a15aab963':
  REPORT-30352 删除不需要的import
  REPORT-30352 直接将RTextAreaBase的border的值改为0，以和8.0版本外观保持一致

designer-base/src/main/java/com/fr/design/gui/syntax/ui/rtextarea/RTextAreaBase.java

@@ -25,6 +25,7 @@ import javax.swing.JTextArea;
 import javax.swing.event.CaretEvent;
 import javax.swing.plaf.ColorUIResource;
 import javax.swing.plaf.TextUI;
+import javax.swing.plaf.basic.BasicBorders;
 import javax.swing.text.AbstractDocument;
 import javax.swing.text.BadLocationException;
 import javax.swing.text.Caret;
@@ -645,7 +646,7 @@ int currentCaretY;							// Used to know when to rehighlight current line.
 		setTabsEmulated(false);
 
 		// Stuff needed by the caret listener below.
-		setMargin(getInsets());
+		setBorder(new BasicBorders.MarginBorder());
 		previousCaretY = currentCaretY = getInsets().top;
 
 		// Stuff to highlight the current line.