From b10c6ab3a83c9dc7a45d4a322c7b206df418fa65 Mon Sep 17 00:00:00 2001
From: Paul Cornett <paulcor@users.noreply.github.com>
Date: Mon, 14 Jan 2019 17:45:25 -0800
Subject: [PATCH] Fix background color from wxControl::GetDefaultAttributes()
 with GTK+3

The default background is not explicitly set on each widget, but is determined
by a parent, usually the TLW. Fixes wxDC default background color for controls.
See #18325
---
 src/gtk/control.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/gtk/control.cpp b/src/gtk/control.cpp
index 772e2f8c8a..85e1e37af7 100644
--- a/src/gtk/control.cpp
+++ b/src/gtk/control.cpp
@@ -267,6 +267,18 @@ wxControl::GetDefaultAttributesFromGTKWidget(GtkWidget* widget,
     attr.font = wxFont(info);
     gdk_rgba_free(fc);
     gdk_rgba_free(bc);
+
+    // Go up the parent chain for a background color
+    while (attr.colBg.Alpha() == 0 && (widget = gtk_widget_get_parent(widget)))
+    {
+        sc = gtk_widget_get_style_context(widget);
+        gtk_style_context_save(sc);
+        gtk_style_context_set_state(sc, stateFlag);
+        gtk_style_context_get(sc, stateFlag, "background-color", &bc, NULL);
+        gtk_style_context_restore(sc);
+        attr.colBg = wxColour(*bc);
+        gdk_rgba_free(bc);
+    }
 #else
     GtkStyle* style;