I have recently upgraded from 2.4 and since then have lost the ability to select images using the TreeDropdownField
when I click on it, nothing happens.
example
$fields->addFieldToTab('Root.Content.Slides', new LiteralField ($name = "literalfield", $content = "<h2>Left Slide Window</h2>"));
$fields->addFieldToTab('Root.Content.Slides', new LiteralField ($name = "literalfield", $content = "<h4>Slide 1</h4>"));
$fields->addFieldToTab('Root.Content.Slides', new TextField('SlideDescriptionShort1', 'Short description'));
$fields->addFieldToTab('Root.Content.Slides', new TextField('SlideDescriptionLong1', 'Long description'));
$fields->addFieldToTab('Root.Content.Slides', new TreeDropdownField('SlidePage1ID', 'Page', 'SiteTree'));
$fields->addFieldToTab("Root.Content.Slides", new SimpleImageField('SlideImage1', 'Image'));