From 7829afc7f6d49cb00956e05f3e1a2c40d8a79047 Mon Sep 17 00:00:00 2001
From: Andrei Shevchenko <andrei.s@mongodb.com>
Date: Tue, 5 May 2026 03:58:17 +0200
Subject: [PATCH] Force xcb platform on Wayland to fix tab drag indicators

Qt Advanced Docking System positions its drop-indicator overlays as top-level Qt::Tool windows using mapToGlobal() + move() to absolute global coordinates. Wayland does not let clients position top-level windows, so during a tab drag the indicators appear at wrong locations. ADS upstream has documented this limitation and recommends running through XWayland.

Set QT_QPA_PLATFORM=xcb;wayland on Linux Wayland sessions so the app runs through XWayland where the positioning works correctly. The semicolon-separated form falls back to wayland on systems without xcb. Honor an explicit user-set QT_QPA_PLATFORM, and provide NOTEPADNEXT_FORCE_NATIVE_WAYLAND=1 as an opt-out.
---
 src/main.cpp | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index e9e2d7bfe..467248d05 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -29,6 +29,25 @@ int main(int argc, char *argv[])
 {
     qSetMessagePattern("[%{time process}] %{if-debug}D%{endif}%{if-info}I%{endif}%{if-warning}W%{endif}%{if-critical}C%{endif}%{if-fatal}F%{endif}: %{message}");
 
+#ifdef Q_OS_LINUX
+    // Qt Advanced Docking System positions its drop-indicator overlays as
+    // top-level Qt::Tool windows using mapToGlobal() + move() to absolute
+    // coordinates. Wayland does not let clients position top-level windows,
+    // so during a tab drag the indicators appear at wrong locations. Run
+    // through XWayland where the positioning works correctly. Honor an
+    // explicit QT_QPA_PLATFORM and an opt-out escape hatch.
+    if (qEnvironmentVariableIsEmpty("QT_QPA_PLATFORM")
+        && !qEnvironmentVariableIsSet("NOTEPADNEXT_FORCE_NATIVE_WAYLAND"))
+    {
+        const QByteArray sessionType = qgetenv("XDG_SESSION_TYPE");
+        const bool isWayland = (sessionType == "wayland")
+                            || qEnvironmentVariableIsSet("WAYLAND_DISPLAY");
+        if (isWayland) {
+            qputenv("QT_QPA_PLATFORM", "xcb;wayland");
+        }
+    }
+#endif
+
     // Set these since other parts of the app references these
     QApplication::setOrganizationName("NotepadNext");
     QApplication::setApplicationName("NotepadNext");