Version:           1.3 (using 4.3.1 (KDE 4.3.1), Debian packages)
Compiler:          cc
OS:                Linux (x86_64) release 2.6.30-1-amd64

Hi,

(I have installed the mplayerthumbs 4:4.3.1-1 package too if that's important.)

The preview widget in Dolphin doesn't always show the playback button. Instead a slideshow is shown displaying frames of the video (correctly).

It seems that this is related to mp4 files by Youtube. I downloaded them with a script:
javascript:if(document.location.href.match(/http:\/\/[a-zA-Z\.]*youtube\.com\/watch/)){document.location.href='http://www.youtube.com/get_video?fmt='+(isHDAvailable?'22':'18')+'&video_id='+swfArgs['video_id']+'&t='+swfArgs['t']}

When I go to another filetype first (avi, mp3) I do always get the playback button. After I trying another filetype like this, the button will show up for mp4 files too. When I close all Dolphin windows now I have to do this again for a new instance of Dolphin.

Regards,
Sladi