Hi Woodstock
This is not a DxO issue but a Canon issue. I had or have exactly the same issue you have as I also use the Canon PPL software and prefer it because of the settings available.
Not getting a response here I raised the issue with Canon, and surprise surprise, Adobe is the only system they think exists on earth.
So, the way I work around this is I process my file and once I have done that, I usually save a JPEG version in the same folder as the RAW file. I normally set my filter to “RGB Images” and can easily find them later. The files I want to print are filed as TIFF files, but instead of filing to the same folder I have created a “X-PRINT” folder and then save the TIFF there when you hit the “Export to Disc”. (The X-Print means the folder sits at the bottom of my folder tree and doesn’t interfere with the rest of the folders.)
Now I go to the X-PRINT folder, click on the photo and EXPORT TO APPLICATION but without processing. This opens PPL and then in the top left corner you can OPEN FILE and once you have navigated to the X-PRINT folder every time thereafter that is what will open first, and you no longer have to navigate to it again. Once in the folder you can then add the photo and drag it onto the print screen.
Bit of a set up but once you have it going it is fairly simple, and it also means all you photos selected for printing are in one location. I also renumber my photos when adding to my PC with the YYYYMMDD-xxxx so if I ever want to find where the TIFF file originated from, I just need to refer to the photo number.
Hope this helps, and trust Canon will update their software at some point in time.