My test Drupal 6.13 site uses Garland theme as default.
I installed OG 6.x 2.0
and created several organic groups.
One of them, say OG7, uses its own theme, Pushbutton.
One new content type, say CT-OG7, has been created to be used only in OG7,
therefore, if I created an instance of this CT-OG7, I set the "Audience" for this instance only to OG7.
I have also created a new view, say View-CT-OG7, that is based on nodes that are of type=CT-OG7.
Although I link to the Page display of this view from the OG7 home page (shown in Pushbutton theme), the view Page display showed in Garland theme.

Then I went back to the View-CT-OG7 configuration and in both, in view defaults and also in view Page display, I visited Theme: Information and in the Theming information window I saw that the theme shown in the drop-down menu was Garland. In both cases I changed the default theme Garland to Pushbutton, then I clicked "Change theme" button, then I clicked "Re-scan template files" button, then OK and then I saved the Changed view.

Nothing changed, the View-CT-OG7 comes again in Garland.

How can I configure the View-CT-OG7 Page display to show in Pushbutton theme?