To answer the FIXME, no, we shouldn't force this. The fullscreen flag…

… implies borderless behavior even though the flag isn't set on the window (in case fullscreen is toggled)

src/video/uikit/SDL_uikitwindow.m

@@ -69,9 +69,6 @@ static int SetupWindowData(_THIS, SDL_Window *window, UIWindow *uiwindow, SDL_bo
 
     window->driverdata = data;
 
-    // !!! FIXME: should we force this? Shouldn't specifying FULLSCREEN
-    // !!! FIXME:  imply BORDERLESS?
-    window->flags |= SDL_WINDOW_FULLSCREEN;        /* window is always fullscreen */
     window->flags |= SDL_WINDOW_SHOWN;            /* only one window on iOS, always shown */
 
     // SDL_WINDOW_BORDERLESS controls whether status bar is hidden.
@@ -84,7 +81,7 @@ static int SetupWindowData(_THIS, SDL_Window *window, UIWindow *uiwindow, SDL_bo
     } else {
         window->flags |= SDL_WINDOW_INPUT_FOCUS;  // always has input focus
 
-        if (window->flags & SDL_WINDOW_BORDERLESS) {
+        if (window->flags & (SDL_WINDOW_FULLSCREEN|SDL_WINDOW_BORDERLESS)) {
             [UIApplication sharedApplication].statusBarHidden = YES;
         } else {
             [UIApplication sharedApplication].statusBarHidden = NO;
@@ -167,7 +164,7 @@ static int SetupWindowData(_THIS, SDL_Window *window, UIWindow *uiwindow, SDL_bo
     /* ignore the size user requested, and make a fullscreen window */
     // !!! FIXME: can we have a smaller view?
     UIWindow *uiwindow = [UIWindow alloc];
-    if (window->flags & SDL_WINDOW_BORDERLESS)
+    if (window->flags & (SDL_WINDOW_FULLSCREEN|SDL_WINDOW_BORDERLESS))
         uiwindow = [uiwindow initWithFrame:[uiscreen bounds]];
     else
         uiwindow = [uiwindow initWithFrame:[uiscreen applicationFrame]];