reset dropdown when drag drop

Report_Viewer.html

@@ -204,6 +204,10 @@
 
         function handleFile(file) {
             if (!file) return;
+            // 重置下拉框到默认占位符选项
+            const dropdown = document.getElementById('fileDropdown');
+            if (dropdown) dropdown.selectedIndex = 0;
+
             const reader = new FileReader();
             reader.onload = (e) => { globalData = e.target.result; processData(globalData); };
             reader.readAsText(file, 'UTF-8');