Add option to enable/disable WS_CLIPCHILDREN window style

CHANGELOG.md

@@ -13,6 +13,7 @@ Unreleased` header.
 
 - On X11, check common alternative cursor names when loading cursor.
 - On Windows, fix so `drag_window` and `drag_resize_window` can be called from another thread.
+- On Windows, remove `WS_CLIPCHILDREN` from the window style.
 
 # 0.29.3
 
@@ -530,7 +531,7 @@ Unreleased` header.
 - On macOS, fix inverted horizontal scroll.
 - **Breaking:** `current_monitor` now returns `Option<MonitorHandle>`.
 - **Breaking:** `primary_monitor` now returns `Option<MonitorHandle>`.
-- On macOS, updated core-* dependencies and cocoa.
+- On macOS, updated core-\* dependencies and cocoa.
 - Bump `parking_lot` to 0.11
 - On Android, bump `ndk`, `ndk-sys` and `ndk-glue` to 0.2. Checkout the new ndk-glue main proc attribute.
 - On iOS, fixed starting the app in landscape where the view still had portrait dimensions.
@@ -572,7 +573,7 @@ Unreleased` header.
 - On Windows, fix `WindowBuilder::with_maximized` being ignored.
 - On Android, minimal platform support.
 - On iOS, touch positions are now properly converted to physical pixels.
-- On macOS, updated core-* dependencies and cocoa
+- On macOS, updated core-\* dependencies and cocoa
 
 # 0.22.1 (2020-04-16)
 
@@ -759,7 +760,7 @@ Unreleased` header.
 
 - On X11, non-resizable windows now have maximize explicitly disabled.
 - On Windows, support paths longer than MAX_PATH (260 characters) in `WindowEvent::DroppedFile`
-and `WindowEvent::HoveredFile`.
+  and `WindowEvent::HoveredFile`.
 - On Mac, implement `DeviceEvent::Button`.
 - Change `Event::Suspended(true / false)` to `Event::Suspended` and `Event::Resumed`.
 - On X11, fix sanity check which checks that a monitor's reported width and height (in millimeters) are non-zero when calculating the DPI factor.
@@ -1101,20 +1102,20 @@ _Yanked_
 - Added event `WindowEvent::HiDPIFactorChanged`.
 - Added method `MonitorId::get_hidpi_factor`.
 - Deprecated `get_inner_size_pixels` and `get_inner_size_points` methods of `Window` in favor of
-`get_inner_size`.
+  `get_inner_size`.
 - **Breaking:** `EventsLoop` is `!Send` and `!Sync` because of platform-dependant constraints,
   but `Window`, `WindowId`, `DeviceId` and `MonitorId` guaranteed to be `Send`.
 - `MonitorId::get_position` now returns `(i32, i32)` instead of `(u32, u32)`.
 - Rewrite of the wayland backend to use wayland-client-0.11
 - Support for dead keys on wayland for keyboard utf8 input
 - Monitor enumeration on Windows is now implemented using `EnumDisplayMonitors` instead of
-`EnumDisplayDevices`. This changes the value returned by `MonitorId::get_name()`.
+  `EnumDisplayDevices`. This changes the value returned by `MonitorId::get_name()`.
 - On Windows added `MonitorIdExt::hmonitor` method
 - Impl `Clone` for `EventsLoopProxy`
 - `EventsLoop::get_primary_monitor()` on X11 will fallback to any available monitor if no primary is found
 - Support for touch event on wayland
 - `WindowEvent`s `MouseMoved`, `MouseEntered`, and `MouseLeft` have been renamed to
-`CursorMoved`, `CursorEntered`, and `CursorLeft`.
+  `CursorMoved`, `CursorEntered`, and `CursorLeft`.
 - New `DeviceEvent`s added, `MouseMotion` and `MouseWheel`.
 - Send `CursorMoved` event after `CursorEntered` and `Focused` events.
 - Add support for `ModifiersState`, `MouseMove`, `MouseInput`, `MouseMotion` for emscripten backend.

src/platform_impl/windows/window_state.rs

@@ -17,10 +17,10 @@ use windows_sys::Win32::{
         SWP_ASYNCWINDOWPOS, SWP_FRAMECHANGED, SWP_NOACTIVATE, SWP_NOMOVE, SWP_NOREPOSITION,
         SWP_NOSIZE, SWP_NOZORDER, SW_HIDE, SW_MAXIMIZE, SW_MINIMIZE, SW_RESTORE, SW_SHOW,
         SW_SHOWNOACTIVATE, WINDOWPLACEMENT, WINDOW_EX_STYLE, WINDOW_STYLE, WS_BORDER, WS_CAPTION,
-        WS_CHILD, WS_CLIPCHILDREN, WS_CLIPSIBLINGS, WS_EX_ACCEPTFILES, WS_EX_APPWINDOW,
-        WS_EX_LAYERED, WS_EX_NOREDIRECTIONBITMAP, WS_EX_TOPMOST, WS_EX_TRANSPARENT,
-        WS_EX_WINDOWEDGE, WS_MAXIMIZE, WS_MAXIMIZEBOX, WS_MINIMIZE, WS_MINIMIZEBOX,
-        WS_OVERLAPPEDWINDOW, WS_POPUP, WS_SIZEBOX, WS_SYSMENU, WS_VISIBLE,
+        WS_CHILD, WS_CLIPSIBLINGS, WS_EX_ACCEPTFILES, WS_EX_APPWINDOW, WS_EX_LAYERED,
+        WS_EX_NOREDIRECTIONBITMAP, WS_EX_TOPMOST, WS_EX_TRANSPARENT, WS_EX_WINDOWEDGE, WS_MAXIMIZE,
+        WS_MAXIMIZEBOX, WS_MINIMIZE, WS_MINIMIZEBOX, WS_OVERLAPPEDWINDOW, WS_POPUP, WS_SIZEBOX,
+        WS_SYSMENU, WS_VISIBLE,
     },
 };
 
@@ -252,7 +252,7 @@ impl WindowFlags {
 
     pub fn to_window_styles(self) -> (WINDOW_STYLE, WINDOW_EX_STYLE) {
         // Required styles to properly support common window functionality like aero snap.
-        let mut style = WS_CAPTION | WS_BORDER | WS_CLIPSIBLINGS | WS_CLIPCHILDREN | WS_SYSMENU;
+        let mut style = WS_CAPTION | WS_BORDER | WS_CLIPSIBLINGS | WS_SYSMENU;
         let mut style_ex = WS_EX_WINDOWEDGE | WS_EX_ACCEPTFILES;
 
         if self.contains(WindowFlags::RESIZABLE) {