It would be useful in the image editor tools, especially for slow processes like refocus, to have an settings with preview history for comparing settings. Say you are using a tool (like refocus), and adjust the settings, then click "try". The tool generates a preview. Currently, if you tweak the settings, and click try again, you lose the last settings and the preview. I suggest that when the preview is generated, an icon or thumbnail get put on a bar across top or bottom the preview window. Now when you tweak the settings, and click try, the new preview is added to the history. By clicking one of the previous thumbnails, you restore the previous preview and settings. You can now switch between histories to compare the results, and select the settings for the final "Ok". On closing the tool, the histories would be deleted. Optionally, using right-click or a button, histories could be deleted from the history bar, to eliminate ones rejected outright. Also, there could be a new preview mode, similar to the light table, where you can do side-by side comparison of the previews, to select the settings to continue from. Reproducible: Always
Thank you for the bug report. As this report hasn't seen any changes in 5 years or more, we ask if you can please confirm that the issue still persists. If this bug is no longer persisting or relevant please change the status to resolved.