fix(Windows): ensure WS_CAPTION is set on undecorated windows

src/Core/App.re

@@ -48,7 +48,7 @@ let quit = (~askNicely=false, ~code=0, app: t) => {
   };
 
   if (Hashtbl.length(app.windows) == 0 || !askNicely) {
-    Revery_Native.uninit();
+    Revery_Native.uninitApp();
 
     // Verify [quit] wasn't called recursively from a beforeQuit handler
     if (!app.isQuitting) {
@@ -253,7 +253,7 @@ let start = init => {
   let dispatchFileOpen = Event.dispatch(appInstance.onFileOpen);
   Callback.register("revery_dispatchFileOpen", dispatchFileOpen);
 
-  Revery_Native.init();
+  Revery_Native.initApp();
 
   let appLoop = () => {
     _flushEvents();

src/Core/Window.re

@@ -628,6 +628,8 @@ let create = (name: string, options: WindowCreateOptions.t) => {
 
   Internal.updateMetrics(window);
 
+  Revery_Native.initWindow(sdlWindow);
+
   window;
 };
 

src/Native/Initialization.re

@@ -1,3 +1,7 @@
-external init: unit => unit = "revery_initialize";
+external initApp: unit => unit = "revery_initializeApp";
+external uninitApp: unit => unit = "revery_uninitializeApp";
 
-external uninit: unit => unit = "revery_uninitialize";
+external _initWindow: Sdl2.Window.nativeWindow => unit =
+  "revery_initializeWindow";
+let initWindow = (w: Sdl2.Window.t) =>
+  _initWindow(w |> Sdl2.Window.getNativeWindow);

src/Native/Revery_Native.c

@@ -11,14 +11,15 @@
 #ifdef WIN32
 #include "ReveryWin32.h"
 #include <combaseapi.h>
+#include <windows.h>
 #elif __APPLE__
 #include "ReveryCocoa.h"
 #import "ReveryAppDelegate.h"
 #else
 #include "ReveryGtk.h"
 #endif
 
-CAMLprim value revery_initialize() {
+CAMLprim value revery_initializeApp() {
 #ifdef __APPLE__
     SDLAppDelegate *sdlDelegate = [NSApp delegate];
     ReveryAppDelegate *delegate = [ReveryAppDelegate newWithSDLDelegate:sdlDelegate];
@@ -32,9 +33,23 @@ CAMLprim value revery_initialize() {
     return Val_unit;
 }
 
-CAMLprim value revery_uninitialize() {
+CAMLprim value revery_uninitializeApp() {
 #ifdef WIN32
     CoUninitialize();
 #endif
     return Val_unit;
 }
+
+
+CAMLprim value revery_initializeWindow(value vWin) {
+    CAMLparam1(vWin);
+    void *win = (void *)vWin;
+#ifdef WIN32
+    HWND window = (HWND)win;
+    int current_style = GetWindowLong(window, GWL_STYLE);
+    SetWindowLong(window, GWL_STYLE, current_style | WS_CAPTION);
+#else
+    UNUSED(win);
+#endif
+    CAMLreturn(Val_unit);
+}