[pitivi] Disable scroll on widgets in scrollable container

[Alexandru Băluț <alexbalut src gnome org>]

commit 31c8fa782b38b51bbe5d59d051b7470d9bfc6f82
Author: Aitik Gupta <aitikgupta gmail com>
Date:   Fri Jan 22 20:42:21 2021 +0530

    Disable scroll on widgets in scrollable container
    
    Fixes #2495

 pitivi/clipproperties.py |  3 ++-
 pitivi/effects.py        |  4 +++-
 pitivi/utils/ui.py       | 18 +++++++++++++-----
 pitivi/utils/widgets.py  | 14 ++++++--------
 4 files changed, 24 insertions(+), 15 deletions(-)
---
diff --git a/pitivi/clipproperties.py b/pitivi/clipproperties.py
index c714f0bf4..6daa1a22b 100644
--- a/pitivi/clipproperties.py
+++ b/pitivi/clipproperties.py
@@ -107,6 +107,8 @@ class ClipProperties(Gtk.ScrolledWindow, Loggable):
         self.helper_box = self.create_helper_box()
         self.clips_box.pack_start(self.helper_box, False, False, 0)
 
+        disable_scroll(vbox)
+
         self.transformation_expander.set_source(None)
         self.title_expander.set_source(None)
         self.color_expander.set_source(None)
@@ -841,7 +843,6 @@ class TransformationProperties(Gtk.Expander, Loggable):
         spinbtn = self.builder.get_object(widget_name)
         handler_id = spinbtn.connect(
             "value-changed", self._on_value_changed_cb, property_name)
-        disable_scroll(spinbtn)
         self.spin_buttons[property_name] = spinbtn
         self.spin_buttons_handler_ids[property_name] = handler_id
 
diff --git a/pitivi/effects.py b/pitivi/effects.py
index 2cfb5bc87..0c1749e21 100644
--- a/pitivi/effects.py
+++ b/pitivi/effects.py
@@ -46,6 +46,7 @@ from pitivi.configure import get_pixmap_dir
 from pitivi.configure import get_ui_dir
 from pitivi.settings import GlobalSettings
 from pitivi.utils.loggable import Loggable
+from pitivi.utils.ui import disable_scroll
 from pitivi.utils.ui import EFFECT_TARGET_ENTRY
 from pitivi.utils.ui import PADDING
 from pitivi.utils.ui import SPACING
@@ -720,7 +721,8 @@ class EffectsPropertiesManager(GObject.Object, Loggable):
         """Creates a widget if the `create_widget` handlers did not."""
         effect_name = effect.get_property("bin-description")
         self.log('UI is being auto-generated for "%s"', effect_name)
-        effect_widget.add_widgets(create_property_widget=self.create_property_widget, with_reset_button=True)
+        effect_widget.add_widgets(create_property_widget_func=self.create_property_widget, 
with_reset_button=True)
+        disable_scroll(effect_widget)
         self._post_configuration(effect, effect_widget)
 
     def do_create_property_widget(self, effect_widget, effect, prop, prop_value):
diff --git a/pitivi/utils/ui.py b/pitivi/utils/ui.py
index 35e472de3..ef59cc3ce 100644
--- a/pitivi/utils/ui.py
+++ b/pitivi/utils/ui.py
@@ -844,13 +844,21 @@ def unset_children_state_recurse(widget, state):
             unset_children_state_recurse(child, state)
 
 
+def disable_scroll_event_cb(widget, unused_event):
+    GObject.signal_stop_emission_by_name(widget, "scroll-event")
+    return False
+
+
 def disable_scroll(widget):
-    """Makes sure the specified widget does not react to scroll events."""
-    def scroll_event_cb(widget, unused_event):
-        GObject.signal_stop_emission_by_name(widget, "scroll-event")
-        return False
+    """Disables scrolling on the specified widget and its children recursively.
+
+    Makes sure the vulnerable widgets do not react to scroll events.
+    """
+    if isinstance(widget, Gtk.Container):
+        widget.foreach(disable_scroll)
 
-    widget.connect("scroll-event", scroll_event_cb)
+    if isinstance(widget, (Gtk.ComboBox, Gtk.Scale, Gtk.SpinButton)):
+        widget.connect("scroll-event", disable_scroll_event_cb)
 
 
 def fix_infobar(infobar):
diff --git a/pitivi/utils/widgets.py b/pitivi/utils/widgets.py
index 8581e8a8b..7aec460dd 100644
--- a/pitivi/utils/widgets.py
+++ b/pitivi/utils/widgets.py
@@ -121,7 +121,6 @@ class TextWidget(Gtk.Box, DynamicWidget):
                 self.combo = Gtk.ComboBoxText.new_with_entry()
                 self.text = self.combo.get_child()
                 self.combo.show()
-                disable_scroll(self.combo)
                 self.pack_start(self.combo, expand=False, fill=False, padding=0)
                 for choice in choices:
                     self.combo.append_text(choice)
@@ -247,7 +246,6 @@ class NumericWidget(Gtk.Box, DynamicWidget):
                 Gtk.Orientation.HORIZONTAL, self.adjustment)
             self.pack_start(self.slider, expand=False, fill=False, padding=0)
             self.slider.show()
-            disable_scroll(self.slider)
             self.slider.set_size_request(width=100, height=-1)
             self.slider.props.draw_value = False
             # Abuse GTK3's progressbar "fill level" feature to provide
@@ -257,8 +255,6 @@ class NumericWidget(Gtk.Box, DynamicWidget):
                 self.slider.set_fill_level(float(default))
                 self.slider.set_show_fill_level(True)
 
-        disable_scroll(self.spinner)
-
     def block_signals(self):
         if self.handler_id:
             self.adjustment.handler_block(self.handler_id)
@@ -484,7 +480,6 @@ class ChoiceWidget(Gtk.Box, DynamicWidget):
         self.pack_start(self.contents, expand=False, fill=False, padding=0)
         self.set_choices(choices)
         self.contents.show()
-        disable_scroll(self.contents)
         cell = self.contents.get_cells()[0]
         cell.props.ellipsize = Pango.EllipsizeMode.END
 
@@ -702,6 +697,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
 
     def show_widget(self, widget):
         self.pack_start(widget, True, True, 0)
+        disable_scroll(widget)
         self.show_all()
 
     def map_builder(self, builder):
@@ -807,7 +803,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
             grid.attach(label, 0, y, 1, 1)
             grid.attach(widget, 1, y, 1, 1)
 
-    def add_widgets(self, create_property_widget, values=None, with_reset_button=False, caps_values=None):
+    def add_widgets(self, create_property_widget_func, values=None, with_reset_button=False, 
caps_values=None):
         """Prepares a Gtk.Grid containing the property widgets of an element.
 
         Each property is on a separate row.
@@ -816,7 +812,8 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
         If there are no properties, returns a "No properties" label.
 
         Args:
-            create_property_widget (function): The function that creates the widget for an effect property.
+            create_property_widget_func (function): The function that creates
+                the widget for an effect property.
             values (dict): The current values of the element props, by name.
                 If empty, the default values will be used.
             with_reset_button (bool): Whether to show a reset button for each
@@ -889,7 +886,7 @@ class GstElementSettingsWidget(Gtk.Box, Loggable):
                 else:
                     prop_value = values[prop.name]
 
-            prop_widget = create_property_widget(self, prop, prop_value)
+            prop_widget = create_property_widget_func(self, prop, prop_value)
             element_name = None
             if isinstance(self.element, Gst.Element):
                 element_name = self.element.get_factory().get_name()
@@ -1162,6 +1159,7 @@ class GstElementSettingsDialog(Loggable):
                                          with_reset_button=True,
                                          values=properties,
                                          caps_values=caps_values)
+        disable_scroll(self.elementsettings)
 
         # Try to avoid scrolling, whenever possible.
         screen_height = self.window.get_screen().get_height()