[meld] Work around bad close button styling in notebooks (#344)

[Kai Willadsen <kaiw src gnome org>]

commit 85d752c48462bb28d407193c97a729bc7c168f43
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Jun 23 09:00:52 2019 +1000

    Work around bad close button styling in notebooks (#344)
    
    It's not clear to me why this happens, but I've tracked it down to us
    using a GtkEventBox as a container in the tab. However, we're not
    stopping doing that, so... here we are.

 data/meld.css                       | 5 +++++
 meld/resources/ui/notebook-label.ui | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/data/meld.css b/data/meld.css
index b7bd5bc8..79f8cd91 100644
--- a/data/meld.css
+++ b/data/meld.css
@@ -55,6 +55,11 @@ meld-find-bar {
     background-color: @theme_bg_color;
 }
 
+/* Work around bad close button styling; see Meld issue #344. */
+.meld-notebook > header tab  button.flat {
+        margin-right: 0;
+}
+
 .meld-notebook-child {
     background-color: @theme_bg_color;
 }
diff --git a/meld/resources/ui/notebook-label.ui b/meld/resources/ui/notebook-label.ui
index 7103912e..8b9f54ee 100644
--- a/meld/resources/ui/notebook-label.ui
+++ b/meld/resources/ui/notebook-label.ui
@@ -33,7 +33,7 @@
             <property name="tooltip_text" translatable="yes">Close Tab</property>
             <property name="image">close_symbolic_image</property>
             <signal name="clicked" handler="on_close_button_clicked" swapped="no"/>
-            <style>on_close_button_clicked
+            <style>
               <class name="small-button"/>
               <class name="flat"/>
             </style>