[BUG?] - The [Project Media] Preview area.
When I mouse over the videos and or image files, there is some kind of white bar that can be moved and if you hold the mouse down it selects a section etc and so on. I have no idea what this 'feature' is, nor do I know how to turn it off (if it is at all possible). The problem I am having is being able to left click on that media and dragging it down to the video layers (Vegas' Tracks). For some reason, when that selection bar thing appears on the media within the Project Media preview area, that's it, I'm no longer able to drag the media down. Again, it could be a bug and if so, hope you can reproduce it and fix it.
Your second problem looks about handling video's in Project Media.
It showes the videofiles if supported.
If you drag over it with the mouse you see a very short content of that video in that button.
If you drag that thumbnail to the timeline you can place it everywhere on each available track. See my video.
To me it looks better if you read the manual good and look also the "Interactive Tutorials" of the Help menu.