From 70d450d086157abd78a9cb0c4365645ace0c3488 Mon Sep 17 00:00:00 2001
From: Fredia Huya-Kouadio <fhuyakou@gmail.com>
Date: Mon, 15 Jul 2024 23:23:44 -0700
Subject: [PATCH] Fix issue causing input lock when drag scrolling a `Tree`
 element on touchscreen devices

Prior to this fix, scrolling via mouse drag on touchscreen devices, and
drag&drop operation on a `TreeItem` element would conflict with each other
preventing the drag scroll from being released when the mouse button is
released.

The issue is addressed by disabling drag&drop when drag scrolling is ongoing.
---
 scene/gui/tree.cpp | 18 ++++++++++++++++++
 scene/gui/tree.h   |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/scene/gui/tree.cpp b/scene/gui/tree.cpp
index b0dfdacad0d..46fcdcf7f6c 100644
--- a/scene/gui/tree.cpp
+++ b/scene/gui/tree.cpp
@@ -5440,6 +5440,24 @@ int Tree::get_drop_section_at_position(const Point2 &p_pos) const {
 	return -100;
 }
 
+bool Tree::can_drop_data(const Point2 &p_point, const Variant &p_data) const {
+	if (drag_touching) {
+		// Disable data drag & drop when touch dragging.
+		return false;
+	}
+
+	return Control::can_drop_data(p_point, p_data);
+}
+
+Variant Tree::get_drag_data(const Point2 &p_point) {
+	if (drag_touching) {
+		// Disable data drag & drop when touch dragging.
+		return Variant();
+	}
+
+	return Control::get_drag_data(p_point);
+}
+
 TreeItem *Tree::get_item_at_position(const Point2 &p_pos) const {
 	if (root) {
 		Point2 pos = p_pos;
diff --git a/scene/gui/tree.h b/scene/gui/tree.h
index e9c93c6e035..3200459b5ae 100644
--- a/scene/gui/tree.h
+++ b/scene/gui/tree.h
@@ -698,6 +698,8 @@ public:
 
 	virtual String get_tooltip(const Point2 &p_pos) const override;
 
+	virtual bool can_drop_data(const Point2 &p_point, const Variant &p_data) const override;
+	virtual Variant get_drag_data(const Point2 &p_point) override;
 	TreeItem *get_item_at_position(const Point2 &p_pos) const;
 	int get_column_at_position(const Point2 &p_pos) const;
 	int get_drop_section_at_position(const Point2 &p_pos) const;