Comment 2 for bug 1266138

I can confirm that this workaround works for me.

I changed this :

    <!-- Keybindings for window tiling -->
    <keybind key="W-Left"> # HalfLeftScreen
      <action name="UnmaximizeFull"/>
      <action name="MoveResizeTo"><x>0</x><y>0</y><height>97%</height><width>50%</width></action>
    </keybind>
    <keybind key="W-Right"> # HalfRightScreen
      <action name="UnmaximizeFull"/>
      <action name="MoveResizeTo"><x>-0</x><y>0</y><height>97%</height><width>50%</width></action>
    </keybind>

... to this :

    <!-- Keybindings for window tiling -->
    <keybind key="W-Left"> # HalfLeftScreen
      <action name="UnmaximizeFull"/>
      <action name="MoveResizeTo"><x>0</x><y>0</y><height>100%</height><width>50%</width></action>
    </keybind>
    <keybind key="W-Right"> # HalfRightScreen
      <action name="UnmaximizeFull"/>
      <action name="MoveResizeTo"><x>-0</x><y>0</y><height>100%</height><width>50%</width></action>
    </keybind>

However, 100% should be the default value for these keybindings.