This release fixes several issues related to copy-paste, improves performance and quality for a few adjustments, and fixes a data loss bug. You can download this using the built-in updater (make sure "Also check for betas" is enabled), or just download it directly from the website: http://www.getpaint.net/ (by the way, please do not directly link to the ZIP files)
I should be able to put out a final (non-beta) release within a week or two.
Here’s what’s changed since v3.5.5:
- Improved: When pasting an image, Paint.NET will be smarter about ensuring it is placed within the area that has been scrolled/zoomed to.
- Improved: Performance and quality of the Curves and Hue/Saturation adjustments.
- Improved: Some minor improvements to memory usage, which should help out a few scenarios on 32-bit systems.
- Fixed: Copy-paste from a Remote Desktop session will no longer be ‘shifted’ by 3 pixels.
- Fixed: Copy-paste from Internet Explorer, Firefox, or Chrome should preserve alpha/transparency.
- Fixed: Copying from Paint.NET and pasting into Windows Live Writer should now work.
- Fixed: Taking a full-screen screenshot with Print Screen on a multimonitor system, where those monitors don’t form a simple rectangle, will now fill the ‘gap area’ with transparent instead of black. (Example: two monitors of the same size, one of which is rotated by 90 degrees)
- Fixed: If Paint.NET is opened without specifying an image to open, and then the default image is modified and saved, then Paint.NET will no longer close that image upon opening another one. This was causing data loss if that default image had layers, and was then saved in a format that did not support layers (anything other than .PDN).
- Fixed: Some systems were showing ‘red X’ thumbnails for .PDN files in Windows Explorer, instead of the real thumbnail.
- Fixed: The EXIF "Creation Software" saved along with images is no longer localized. This prevents certain languages from seeing "Paint.NET ????? v3.5.6" in the image properties (metadata).
paint.net blog 
Speaking of pasting from a Remote Desktop, this is something that I frequently do. I often remote into servers in other branches on other continents. (Usually taking various screen captures of our software.) This often takes a significant amount of time due to the image sizes.
However, one particularly sticking point is how Paint.Net deals with this. It waits until the full file is transferred before realizing that the image size is too large to fit into the current window. After expanding this, it then tries to download the image yet again.
Is there any way that you could determine the image size at the start of the transfer and adjust appropriately? To avoid this problem, I will often paste into Excel or Word, then move it locally from there into Paint.Net.
Regards.
There is no way to only transfer a small part of the clipboard data. However, try out 3.5.6. It should only transfer the clipboard data once.
The smart paste cripples some useful flow:
1. Create an HTML page/application -> grab screen
2. Paste into PDN
3. Zoom into a problematic area
4. Fix problematic area by fixing HTML/Application -> grab screen again
5. Paste Again into PDN to the same canvas as in step 2
Old Behavior:
You would see the new changes in the view port without scrolling.
New Behavior:
You need to scroll to see the changes.
Suggest fix:
If the pasted image is the same as the canvas then paste it into 0,0 (as before)
Ok so zoom back out before pasting again. Ctrl+B.
Oh wait — I see what you mean now.
Thank you for the bugfixes!
Copy/Paste from Firefox/Chrome/… really annoyed me.
Thank you for fixing it!
Awesome. Works great with Window Clippings 3’s “Copy to clipboard” action and its alpha channel support.
Do make sure you’re using premultiplied alpha with CF_DIB/CF_DIBV5, if you aren’t already.
Thank you for fixing the Remote Desktop copy/pasting! I do it often and that pixel problem drove me nuts. I usually ended up taking a full screenshot and cropping the window I need rather than using the far-more-convenient Alt+Print Screen.