REPORT-59089 【主题切换】主题比较多有滚动条，右侧主题的勾选图标有点显示不全

【问题原因】
待定

【改动思路】
绘制单元格样式预览内容前清空画布

designer-base/src/main/java/com/fr/design/mainframe/theme/TemplateThemeListPane.java

@@ -2,7 +2,6 @@ package com.fr.design.mainframe.theme;
 
 import com.fr.base.theme.TemplateTheme;
 import com.fr.base.theme.TemplateThemeConfig;
-import com.fr.base.theme.settings.ThemeThumbnail;
 import com.fr.design.designer.IntervalConstants;
 import com.fr.design.dialog.BasicPane;
 import com.fr.design.event.ChangeEvent;
@@ -13,6 +12,7 @@ import com.fr.stable.StringUtils;
 
 import javax.swing.BorderFactory;
 import javax.swing.JPanel;
+import javax.swing.ScrollPaneConstants;
 import java.awt.BorderLayout;
 import java.awt.Dimension;
 import java.awt.GridLayout;
@@ -64,14 +64,14 @@ public class TemplateThemeListPane<T extends TemplateTheme> extends BasicPane {
         setLayout(FRGUIPaneFactory.createBorderLayout());
         setPreferredSize(new Dimension(CONTENT_WIDTH, CONTENT_HEIGHT));
 
-        contentListPane.setBorder(BorderFactory.createEmptyBorder(BLOCK_GAP, 0, BLOCK_GAP, 0));
+        contentListPane.setBorder(BorderFactory.createEmptyBorder(BLOCK_GAP, 0, BLOCK_GAP, 10));
         contentListPane.setLayout(new GridLayout(0, BLOCK_COUNT_ROW_LINE, BLOCK_GAP, BLOCK_GAP));
         fillContentListPane();
 
-        JPanel wrapper = FRGUIPaneFactory.createBorderLayout_S_Pane();
+        UIScrollPane scrollPane = new UIScrollPane(contentListPane);
-        wrapper.add(contentListPane, BorderLayout.NORTH);
+        scrollPane.setPreferredSize(new Dimension(CONTENT_WIDTH, CONTENT_HEIGHT));
-
+        scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
-        UIScrollPane scrollPane = new UIScrollPane(wrapper);
+        scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
         scrollPane.setBorder(BorderFactory.createEmptyBorder());
         add(scrollPane, BorderLayout.CENTER);