From 55b24b93b406d8213e7eaa7c0b319f138225c9c9 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Wed, 26 Sep 2018 11:17:43 -0700
Subject: [PATCH] Fixed bug 4265 - SDL window falls to the bottom of the screen
 when dragged down and stuck there

Alexei

On WM_WINDOWPOSCHANGED event, WIN_UpdateClipCursor() is called. SDL_WINDOW_INPUT_FOCUS is set even when the mouse pointer is not inside the SDL window and therefore ClipCursor(&rect) is called. When dragging the window and rect.bottom=800 (i.e. the bottom edge of the screen) the SDL window is clipped to the bottom of the screen and it is not possible to move it back to the center of the screen.
---
 src/video/windows/SDL_windowsevents.c | 7 +++++++
 src/video/windows/SDL_windowswindow.c | 6 +++++-
 src/video/windows/SDL_windowswindow.h | 1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index 5773f3995..e961cf568 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -414,6 +414,13 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
         }
         break;
 
+    case WM_NCACTIVATE:
+        {
+            /* Don't immediately clip the cursor in case we're clicking minimize/maximize buttons */
+            data->skip_update_clipcursor = SDL_TRUE;
+        }
+        break;
+
     case WM_ACTIVATE:
         {
             POINT cursorPos;
diff --git a/src/video/windows/SDL_windowswindow.c b/src/video/windows/SDL_windowswindow.c
index ba5ef0583..45463c4c7 100644
--- a/src/video/windows/SDL_windowswindow.c
+++ b/src/video/windows/SDL_windowswindow.c
@@ -904,7 +904,11 @@ WIN_UpdateClipCursor(SDL_Window *window)
     SDL_Mouse *mouse = SDL_GetMouse();
     RECT rect;
 
-    if (data->focus_click_pending) {
+    if (data->in_title_click || data->focus_click_pending) {
+        return;
+    }
+    if (data->skip_update_clipcursor) {
+        data->skip_update_clipcursor = SDL_FALSE;
         return;
     }
 
diff --git a/src/video/windows/SDL_windowswindow.h b/src/video/windows/SDL_windowswindow.h
index 0dacff6a5..b738c3494 100644
--- a/src/video/windows/SDL_windowswindow.h
+++ b/src/video/windows/SDL_windowswindow.h
@@ -44,6 +44,7 @@ typedef struct
     SDL_bool in_border_change;
     SDL_bool in_title_click;
     Uint8 focus_click_pending;
+    SDL_bool skip_update_clipcursor;
     SDL_bool windowed_mode_was_maximized;
     SDL_bool in_window_deactivation;
     RECT cursor_clipped_rect;