We have seen reports of slow brushing and masking and have made this a high priority to solve as soon as possible. Here are some suggestions to try as we work to resolve the issue.
If you are experiencing slow or laggy masking or brushing performance with ON1 Photo RAW 2019 when using the brush or masking tools, we would recommend the following:
1. If you are running ON1 Photo RAW 2019 on the Windows OS, please make sure your GPU driver has been updated by following the steps in this article.
2. Adjust the size of the program window to be smaller than your display size.
3. Prior to doing any masking or brushing - turn off or disable all other filters or local adjustments in your stack other than the one you're are working on.
4. Close the Presets/Filters panes on left hand side, so that only the list is showing (and not thumbnails)
5. Disconnect your tablet and/or external display prior to launching ON1 Photo RAW 2019 and editing/masking.
* Again, these are only temporary workarounds. We are actively working on resolving this issue as soon as possible. If you are still having trouble and if none of these suggestions are helpful, please contact Technical Support.