diff --git a/app/src/layout/Wnd.ts b/app/src/layout/Wnd.ts
index 3abc55c07..6b4daef7c 100644
--- a/app/src/layout/Wnd.ts
+++ b/app/src/layout/Wnd.ts
@@ -332,7 +332,6 @@ export class Wnd {
                 return;
             }
 
-
             if (targetWndElement.contains(document.querySelector(`[data-id="${tabId}"]`))) {
                 return;
             }
diff --git a/app/src/protyle/util/hasClosest.ts b/app/src/protyle/util/hasClosest.ts
index a650eebb9..a8b1aa760 100644
--- a/app/src/protyle/util/hasClosest.ts
+++ b/app/src/protyle/util/hasClosest.ts
@@ -120,7 +120,7 @@ export const hasClosestByClassName = (element: Node, className: string, top = fa
     let e = element as HTMLElement;
     let isClosest = false;
     while (e && !isClosest && (top ? e.tagName !== "BODY" : !e.classList.contains("protyle-wysiwyg"))) {
-        if (e.classList.contains(className)) {
+        if (e.classList?.contains(className)) {
             isClosest = true;
         } else {
             e = e.parentElement;
diff --git a/app/src/window/setHeader.ts b/app/src/window/setHeader.ts
index c954b7e88..fea887d42 100644
--- a/app/src/window/setHeader.ts
+++ b/app/src/window/setHeader.ts
@@ -23,7 +23,7 @@ export const setTabPosition = () => {
         const headerElement = item.headersElement.parentElement;
         const rect = headerElement.getBoundingClientRect()
         const dragElement = headerElement.querySelector('.item--readonly .fn__flex-1') as HTMLElement
-        if (rect.top === 0) {
+        if (rect.top <= 0) {
             dragElement.style.height = dragElement.parentElement.clientHeight + "px"
             // @ts-ignore
             dragElement.style.WebkitAppRegion = "drag";