Resolves: tdf#143720 treeview not resizing to fill available space

Change-Id: I041c3a743b8624f49bfe57e8a4469535e334e5dc
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/120067
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/sw/source/ui/index/cnttab.cxx b/sw/source/ui/index/cnttab.cxx
index 397e062..ffddc80 100644
--- a/sw/source/ui/index/cnttab.cxx
+++ b/sw/source/ui/index/cnttab.cxx
@@ -513,7 +513,8 @@ SwAddStylesDlg_Impl::SwAddStylesDlg_Impl(weld::Window* pParent,
        aWidths.push_back(m_xHeaderTree->get_pixel_size(sTitle).Width() + nPadding);
    }
    m_xHeaderTree->set_column_fixed_widths(aWidths);
    auto nWidth = std::accumulate(aWidths.begin(), aWidths.end(), 0);
    auto nWidth = std::accumulate(aWidths.begin(), aWidths.end(),
                                  Application::GetSettings().GetStyleSettings().GetScrollBarSize());
    m_xHeaderTree->set_size_request(nWidth, m_xHeaderTree->get_height_rows(15));

    int nRow(0);
@@ -576,7 +577,7 @@ SwAddStylesDlg_Impl::SwAddStylesDlg_Impl(weld::Window* pParent,

IMPL_LINK(SwAddStylesDlg_Impl, TreeSizeAllocHdl, const Size&, rSize, void)
{
    auto nWidth = rSize.Width();
    auto nWidth = rSize.Width() - Application::GetSettings().GetStyleSettings().GetScrollBarSize();

    std::vector<int> aWidths;
    aWidths.push_back(0);
diff --git a/sw/uiconfig/swriter/ui/assignstylesdialog.ui b/sw/uiconfig/swriter/ui/assignstylesdialog.ui
index 81f8444..83d150e 100644
--- a/sw/uiconfig/swriter/ui/assignstylesdialog.ui
+++ b/sw/uiconfig/swriter/ui/assignstylesdialog.ui
@@ -180,6 +180,7 @@
                    <property name="visible">True</property>
                    <property name="can_focus">False</property>
                    <property name="halign">start</property>
                    <property name="hexpand">True</property>
                    <property name="column_spacing">12</property>
                    <child>
                      <object class="GtkButtonBox" id="buttonbox1">