MessageInput: Set min height for vertical scrollbar

Fixes #9574, #8980

gajim/chat_control_base.py

@@ -1567,22 +1567,6 @@ class ScrolledWindow(Gtk.ScrolledWindow):
         self.get_style_context().add_class('scrolled-no-border')
         self.get_style_context().add_class('no-scroll-indicator')
         self.get_style_context().add_class('scrollbar-style')
+        self.get_style_context().add_class('one-line-scrollbar')
         self.set_shadow_type(Gtk.ShadowType.IN)
-
-    def do_get_preferred_height(self):
-        min_height, natural_height = Gtk.ScrolledWindow.do_get_preferred_height(self)
-        # Gtk Bug: If policy is set to Automatic, the ScrolledWindow
-        # has a min size of around 46-82 depending on the System. Because
-        # we want it smaller, we set policy NEVER if the height is < 90
-        # so the ScrolledWindow will shrink to around 26 (1 line height).
-        # Once it gets over 90 its no problem to restore the policy.
-        if natural_height < 90:
-            GLib.idle_add(self.set_policy,
-                          Gtk.PolicyType.AUTOMATIC,
-                          Gtk.PolicyType.NEVER)
-        else:
-            GLib.idle_add(self.set_policy,
-                          Gtk.PolicyType.AUTOMATIC,
-                          Gtk.PolicyType.AUTOMATIC)
-
-        return min_height, natural_height
+        self.set_policy(Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)

gajim/data/style/gajim.css

@@ -21,6 +21,7 @@
 .scrollbar-style scrollbar trough {background-color:@theme_base_color; }
 .scrollbar-style scrollbar {border:none; }
 .scrollbar-style slider {min-width: 3px; background-color: #a0a3a4}
+.one-line-scrollbar scrollbar.vertical slider { min-height: 20px; }
 
 .actionbar-no-border box {border: none}
 .actionbar-no-border button {