diff --git a/src/plugins/platforms/wasm/qwasmwindow.cpp b/src/plugins/platforms/wasm/qwasmwindow.cpp
index 68d9d2eb1d5..9ec15d631ad 100644
--- a/src/plugins/platforms/wasm/qwasmwindow.cpp
+++ b/src/plugins/platforms/wasm/qwasmwindow.cpp
@@ -392,10 +392,10 @@ void QWasmWindow::setWindowFlags(Qt::WindowFlags flags)
     if (flags.testFlag(Qt::WindowStaysOnTopHint) != m_flags.testFlag(Qt::WindowStaysOnTopHint))
         m_compositor->windowPositionPreferenceChanged(this, flags);
     m_flags = flags;
+    dom::syncCSSClassWith(m_qtWindow, "frameless", !hasFrame());
     dom::syncCSSClassWith(m_qtWindow, "has-border", hasBorder());
     dom::syncCSSClassWith(m_qtWindow, "has-shadow", hasShadow());
-    dom::syncCSSClassWith(m_qtWindow, "has-title", flags.testFlag(Qt::WindowTitleHint));
-    dom::syncCSSClassWith(m_qtWindow, "frameless", flags.testFlag(Qt::FramelessWindowHint));
+    dom::syncCSSClassWith(m_qtWindow, "has-title", hasTitleBar());
     dom::syncCSSClassWith(m_qtWindow, "transparent-for-input",
                           flags.testFlag(Qt::WindowTransparentForInput));
 
@@ -578,16 +578,25 @@ void QWasmWindow::requestUpdate()
     m_compositor->requestUpdateWindow(this, QWasmCompositor::UpdateRequestDelivery);
 }
 
+bool QWasmWindow::hasFrame() const
+{
+    return !m_flags.testFlag(Qt::FramelessWindowHint);
+}
+
 bool QWasmWindow::hasBorder() const
 {
-    return !m_state.testFlag(Qt::WindowFullScreen) && !m_flags.testFlag(Qt::FramelessWindowHint)
+    return hasFrame() && !m_state.testFlag(Qt::WindowFullScreen) && !m_flags.testFlag(Qt::SubWindow)
             && !windowIsPopupType(m_flags);
 }
 
+bool QWasmWindow::hasTitleBar() const
+{
+    return hasBorder() && m_flags.testFlag(Qt::WindowTitleHint);
+}
+
 bool QWasmWindow::hasShadow() const
 {
-    return !m_flags.testFlag(Qt::NoDropShadowWindowHint)
-            && !m_flags.testFlag(Qt::FramelessWindowHint);
+    return hasBorder() && !m_flags.testFlag(Qt::NoDropShadowWindowHint);
 }
 
 bool QWasmWindow::hasMaximizeButton() const
diff --git a/src/plugins/platforms/wasm/qwasmwindow.h b/src/plugins/platforms/wasm/qwasmwindow.h
index 422a2ea464c..8f8e41a4979 100644
--- a/src/plugins/platforms/wasm/qwasmwindow.h
+++ b/src/plugins/platforms/wasm/qwasmwindow.h
@@ -103,6 +103,8 @@ private:
     static constexpr auto minSizeForRegularWindows = 100;
 
     void invalidate();
+    bool hasFrame() const;
+    bool hasTitleBar() const;
     bool hasBorder() const;
     bool hasShadow() const;
     bool hasMaximizeButton() const;