Bug 1745398 - fix fullscreen button in hamburger panel now that hiding panels...

        <toolbarbutton id="appMenu-fullscreen-button2"

                       class="subviewbutton subviewbutton-iconic"

                       data-l10n-id="appmenuitem-fullscreen"

                       observes="View:FullScreen"

                       type="checkbox"

                       closemenu="auto"

                       onclick="if (event.button == 0) this.closest('panel').hidePopup();"

                       tooltip="dynamic-shortcut-tooltip"/>

# Note that we're custom-handling this click to make sure the panel disappears

# before entering fullscreen, as it does some odd moving about on the screen

# in the middle of the fullscreen transition otherwise.

                       oncommand="

                         this.closest('panel').hidePopup();

                         setTimeout(() => BrowserFullScreen(), 0);

                       "

                       tooltip="dynamic-shortcut-tooltip">

           <observes element="View:FullScreen" attribute="checked"/>

        </toolbarbutton>

      </toolbaritem>

      <toolbarseparator/>

      <toolbarbutton id="appMenu-settings-button"