Frames don't show in Flatpak

I have an application which works fine from a terminal or as a deb package. As a Flatpak the frame borders for GtkMessageDialogs and GtkAboutDialogs disappear, leaving the messages floating in space.
Might it be related to this message? Gtk-Message:…: Failed to load module “appmenu-gtk-module”

What distro do you use? Which version of GTK is the app made for? Can we see your project’s code on GitHub? We need more information

Distro: Ubuntu Budgie 20.10
[chrisofbristol has edited the following two lines to show the versions of Gtk and Glade more clearly]
Gtk version: The application has this statement: gi.require_version(‘Gtk’, ‘3.0’)
Glade: 3.38.22
Code: Flatpak only at test stage.

        self.messageInfo = self.builder.get_object('messagedialogInfo')
        self.messageInfo.format_secondary_text(message)
        self.result = self.messageInfo.run() ; self.messageInfo.hide()

Aaaargh! Someone else has edited my post!

GTK and Glade are two different things.

It’s kind of pointless to show the code loading a UI description file, and not also show the UI description file for that object.

Can you please take a screenshot of what’s the output?

Flatpak: Bottom half of info panel show in image - no surround and no way in that type of widget to add or remove it.

gtk

deb package: Looks fine.

gtkx

  <object class="GtkMessageDialog" id="messagedialogInfo">
    <property name="can-focus">False</property>
    <property name="can-default">True</property>
    <property name="type">popup</property>
    <property name="type-hint">utility</property>
    <property name="gravity">center</property>
    <property name="transient-for">window</property>
    <property name="buttons">close</property>
    <child internal-child="vbox">
      <object class="GtkBox">
        <property name="can-focus">False</property>
        <property name="orientation">vertical</property>
        <property name="spacing">2</property>
        <child internal-child="action_area">
          <object class="GtkButtonBox">
            <property name="can-focus">False</property>
            <property name="layout-style">end</property>
            <child>
              <placeholder/>
            </child>
            <child>
              <placeholder/>
            </child>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">False</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <placeholder/>
        </child>
      </object>
    </child>
    <child type="titlebar">
      <placeholder/>
    </child>
  </object>

some unrelated hate on frames in UI used to be here

Anyway, the answer to the actual question is that flatpak has installed a newer version of GTK than your system has. The frames must have been removed in a recent release

EDIT: Just noticed that .deb version’s window is simply smaller. Can you show the whole window?

My second post has this line

The statement gi.require_version would have caused the program to abort if that was not the case.

The answer was to use a different Flatpak platform. It works properly in the Gnome, but not in the Freedesktop one.