Clamp ex-date to transaction date when date is moved earlier

Issue: #5439

Author: buchen

name.abuchen.portfolio.ui/src/name/abuchen/portfolio/ui/dialogs/transactions/AccountTransactionDialog.java

@@ -292,6 +292,15 @@ public void widgetSelected(SelectionEvent e)
                 if (exDate.checkBox.isVisible() && exDate.checkBox.getSelection())
                 {
                     suggestExDate(exDate);
+
+                    var currentExDate = model().getExDate();
+                    var newTxDate = model().getDate();
+                    if (currentExDate != null && currentExDate.toLocalDate().isAfter(newTxDate))
+                    {
+                        exDate.date.setSelection(newTxDate);
+                        model().setExDate(newTxDate.atStartOfDay());
+                    }
+
                     toggleExDatePicker(exDate, true);
                 }
             });