In previous releases, pressing and holding the mouse button down on the enhanced image in single-image view mode displayed the original image. Now, the space bar must be pressed to show the original image and compare it to the enhanced image.
This is unwanted and annoying behavior, requiring a switch from mouse to keyboard to compare original/enhanced version while using the mouse to adjust enhancements. It is inconsistent with the other two viewing modes (side-by-side and split-screen) which still require mouse interaction.
Pressing the “show original” icon (the eye) causes the original image to be displayed, but then holding the mouse down on the image cancels the original display, un-highlights the eye icon, and shows the enhanced image. This is inconsistent behavior, requiring mouse interaction in single-image view mode.
Finally, when previewing faces, the new shortcut key space-F shows the original faces while retaining the yellow face frames on the screen. It is not possible to use the space key to show the entire original image, while pressing and holding the mouse button on the image used to do this IIRC.
Topaz Photo AI 3.1.0 on Windows