From [ANNOUNCE: xfwm4 4.13.1 released][1]:

> Release notes for 4.13.1
> ========================
> [Please note that this is a development release.]
>
> Adam Purkrt (3):
>       Fix to erratic unmaximization by dragging
>       Keep grip in proportion
>       Typo in clientMoveTile
>
> Andre Miranda (2):
>       I18n: Update translation pt_BR (100%).
>       Fix memory leaks in tabwin
>
> Andrey Alekseenkov (1):
>       Fix logic error in bottom struts validation
>
> Błażej Szczygieł (1):
>       compositor: remove old vblank code
>
> David Siroky (1):
>       Raise window while cycling
>
> Marcel Partap (1):
>       Do not prevent ALT+Mouse resizing for borderless maximized
> windows.
>
> Olivier Fourdan (38):
>       Post release tag bump.
>       netwm: avoid spurious warning on restart
>       placement: Use primary monitor as default
>       Revert "Add PointerMotionHintMask"
>       Use ximerama indices for _NET_WM_FULLSCREEN_MONITORS
>       Fix typo in flag name
>       Flush display to catch possible errors
>       compositor: update presentproto requirement
>       compositor: Remove vblank option
>       compositor: Remove present env var
>       screen: Fix broken monitor index
>       compositor: Disable XPresent on error
>       compositor: check XPresent before GLX
>       Fix maximized size increment regression
>       main: Only allow for the x11 gdk backend
>       compositor: add command line option for vblank
>       compositor: fix clipping region with zooming
>       client: Make sure to redraw when removing maximized
>       screen: Use computed screen size instead of xlib
>       main: keep xfwm4_error_quark private
>       display: Fix warning in trace message
>       stacking: Raise ancestor on activate if different from window
>       pixmap: Avoid warning without icon
>       stacking: Raise on activate w/out click-to-focus
>       Build: Fix warnings with newer gtk+
>       trace: rework traces
>       build: Fix warnings and errors
>       display: Add convenient display functions
>       Use convenient display functions
>       compositor: avoid damage errors
>       compositor: Do not repaint if region is empty
>       compositor: Print the GL renderer used
>       compositor: Skip ARGB10 GLX configs
>       netwm: Fix adding maximized state
>       client: Check when GTK_FRAME_EXTENTS has changed
>       client: Check GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED
>       compositor: Add support for NET_WM_BYPASS_COMPOSITOR
>       Release 4.13.1!
>
> P. Pronk (1):
>       client: Maximize on expected output
>
> Stephane Gourichon (1):
>       Fix build out of tree
>
> Unit 193 (1):
>       Fix a spelling mistake.
>
> Viktor Odintsev (32):
>       Prepare to GTK3
>       Port most of GUI stuff to GTK3
>       Implement RangeDebouncer
>       Implement a new DND separator
>       Replace inline pixbuf with gresource
>       Handle gtk_screen_width/height deprecation
>       Handle gtk_button_set_alignment deprecation
>       Introduce xfwm-common static library
>       Load default icon from icon theme
>       Handle GDK display/screen/monitor deprecations
>       Remove deprecated gdk_screen_make_display_name
>       Replace gdk_error_trap_pop with gdk_error_trap_pop_ignored
>       icons: replace gdk_pixbuf_get_from_drawable with
> gdk_pixbuf_get_from_surface
>       Remove usage of deprecated macroses and private fields
>       icons: use cairo-xlib-xrender to draw window's preview
>       Remove black_gc and white_gc
>       Implement GTK2-like style calculator
>       Implement cairo drawing
>       tabwin: complete GTK3 port, add CSS support
>       poswin: remove deprecations
>       Fix remaining deprecations
>       compositor: fix possible infinite loop
>       events: replace client_event with event filter
>       Fix compilation with --disable-compositor
>       menu: remove deprecations
>       client: remove X error traps
>       tabwin: fix initial sizing
>       Add xfconf 4.13 support
>       main: add support for multiple screens with GDK 3
>       Fix some build warnings
>       device: Implement XI2 event handling
>       Replace XEvent with XfwmEvent + add xfwm_device_* grabs usage
>
> And translations updates from:

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This mainly fixes bug *Only fourth of the screen shown with windows
scaling 2x* [1].

While at it, apply all regression fixes from the Xfwm master branch.

[1]: https://bugzilla.xfce.org/show_bug.cgi?id=14566