diff --git a/src/checkbox/src/Checkbox.tsx b/src/checkbox/src/Checkbox.tsx
index b817b092b..faf56c2af 100644
--- a/src/checkbox/src/Checkbox.tsx
+++ b/src/checkbox/src/Checkbox.tsx
@@ -290,10 +290,12 @@ export default defineComponent({
         onKeydown={handleKeyDown}
         onClick={handleClick}
         onMousedown={() => {
-          const userCallBack = window.onselectstart
-          window.onselectstart = () => false
+          const preventDefault = (e: Event): void => {
+            e.preventDefault()
+          }
+          window.addEventListener('selectstart', preventDefault)
           setTimeout(() => {
-            window.onselectstart = userCallBack
+            window.removeEventListener('selectstart', preventDefault)
           }, 0)
         }}
       >
diff --git a/src/data-table/src/TableParts/Body.tsx b/src/data-table/src/TableParts/Body.tsx
index 35d426f97..01f3f3527 100644
--- a/src/data-table/src/TableParts/Body.tsx
+++ b/src/data-table/src/TableParts/Body.tsx
@@ -143,12 +143,9 @@ export default defineComponent({
       checked: boolean,
       shiftKey: boolean
     ): void {
-      const lastKey = lastSelectedKey
-      lastSelectedKey = tmNode.key
-
       if (shiftKey) {
         const lastIndex = paginatedDataRef.value.findIndex(
-          (item) => item.key === lastKey
+          (item) => item.key === lastSelectedKey
         )
         if (lastIndex !== -1) {
           const currentIndex = paginatedDataRef.value.findIndex(
@@ -167,6 +164,8 @@ export default defineComponent({
           } else {
             doUncheck(rowKeysToCheck)
           }
+          lastSelectedKey = tmNode.key
+          return
         }
       }
 
@@ -175,6 +174,7 @@ export default defineComponent({
       } else {
         doUncheck(tmNode.key)
       }
+      lastSelectedKey = tmNode.key
     }
     function getScrollContainer (): HTMLElement | null {
       if (virtualScrollRef.value) {