Merge pull request #21 in ~HADES/design from ~JOE.JIANG/design:REPORT-25159 to release/10.0

* commit 'c9a8b7dc90a9b7cfbe7eb980984aa94227eaef34':
  REPORT-25159 单元格元素-高级-显示值，删除公式后点击撤销公式显示会丢失

designer-realize/src/main/java/com/fr/quickeditor/cellquick/CellDSColumnEditor.java

@@ -1188,7 +1188,8 @@ public class CellDSColumnEditor extends CellQuickEditor {
                     Object value = cellElement.getValue();
                     if (value instanceof DSColumn) {
                         DSColumn dSColumn = (DSColumn) (cellElement.getValue());
-                        dSColumn.setResult(this.formulaField.getFormulaText());
+                        dSColumn.setResult(StringUtils.isEmpty(this.formulaField.getFormulaText()) ?
+                                null : this.formulaField.getFormulaText());
                     }
                 }
             }