How to set the default height of LayoutRoot.BottomSide

[AndersChen123]

This is the code I use:

<DockingManager AllowDrop="True"
                        IsVirtualizingAnchorable="False"
                        IsVirtualizingDocument="False">
            <DockingManager.Theme>
                <Vs2013LightTheme />
            </DockingManager.Theme>
            <LayoutRoot>
                <LayoutPanel Orientation="Horizontal">
                    <LayoutDocumentPane>
                        <LayoutDocument Title="Document1"
                                        CanFloat="False"
                                        ContentId="D1">
                            <TextBlock Text="test 1" />
                        </LayoutDocument>
                        <LayoutDocument Title="Document2"
                                        CanFloat="False"
                                        ContentId="D2">
                            <TextBlock Text="test 2" />
                        </LayoutDocument>
                    </LayoutDocumentPane>
                </LayoutPanel>
                <LayoutRoot.LeftSide>
                    <LayoutAnchorSide>
                        <LayoutAnchorGroup>
                            <LayoutAnchorable Title="Folders"
                                              AutoHideMinWidth="200"
                                              AutoHideWidth="200"
                                              CanClose="False"
                                              CanDockAsTabbedDocument="False"
                                              CanFloat="False"
                                              CanHide="False"
                                              ContentId="Folders">
                                <Grid>
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="Auto" />
                                        <RowDefinition Height="Auto" />
                                        <RowDefinition />
                                    </Grid.RowDefinitions>
                                    <TextBox HorizontalAlignment="Stretch" Visibility="Collapsed" />
                                </Grid>
                            </LayoutAnchorable>
                        </LayoutAnchorGroup>
                    </LayoutAnchorSide>
                </LayoutRoot.LeftSide>
                <LayoutRoot.RightSide>
                    <LayoutAnchorSide>
                        <LayoutAnchorGroup>
                            <LayoutAnchorable Title="Channels"
                                              AutoHideMinWidth="170"
                                              AutoHideWidth="170"
                                              CanClose="False"
                                              CanDockAsTabbedDocument="False"
                                              CanFloat="False"
                                              CanHide="False"
                                              ContentId="Channels">
                                <ListBox SelectionMode="Extended" />
                            </LayoutAnchorable>
                            <LayoutAnchorable Title="Bins"
                                              AutoHideMinWidth="170"
                                              AutoHideWidth="170"
                                              CanClose="False"
                                              CanDockAsTabbedDocument="False"
                                              CanFloat="False"
                                              CanHide="False"
                                              ContentId="SavedBins">
                                <ListBox SelectionMode="Extended" />
                            </LayoutAnchorable>
                        </LayoutAnchorGroup>
                    </LayoutAnchorSide>
                </LayoutRoot.RightSide>
                <LayoutRoot.BottomSide>
                    <LayoutAnchorSide>
                        <LayoutAnchorGroup>
                            <LayoutAnchorable Title="Log"
                                              AutoHideHeight="200"
                                              AutoHideMinHeight="200"
                                              CanClose="False"
                                              CanDockAsTabbedDocument="False"
                                              CanFloat="False"
                                              CanHide="False"
                                              ContentId="Log">
                                <TextBox Height="200"
                                         HorizontalAlignment="Stretch"
                                         VerticalAlignment="Stretch"
                                         AcceptsReturn="True"
                                         FontSize="10pt" />
                            </LayoutAnchorable>
                        </LayoutAnchorGroup>
                    </LayoutAnchorSide>
                </LayoutRoot.BottomSide>
            </LayoutRoot>
        </DockingManager>

When I click on the "pin" glyph of BottomSide, its height becomes 0. But the RightSide works correctly, LeftSide sometimes does not work correctly.
How can I solve this?

Best regards.

.NET 4.7.2
AvalonDock 4.60.1

AvalonDockTest.zip