We shouldn't call LSCopyApplicationForMIMEType() from content processes because it depends on file system access. That fails when called from our sandboxed content processes due to filesystem restrictions which has a side effect of reverting the assigned handler to the default.

Tl dr, drag-and-drop triggers a call to LSCopyApplicationForMIMEType() to lookup the handler application for a given MIME type. I'll hopefully be able to do a mozregression test in the next couple of days, but anecdotally this only started with Firefox Quantum, did not happen with any Firefox 56 and below. There have been no updates to CS5 or CS6 products for a number of years so any updates to those products can be ruled out as a cause of the issues. This behaviour did not happen with any versions of Firefox previous to Quantum. Doesn't happen on any other websites I use, but I assume they use different methods for uploading files. I've only noticed this issue with this upload button on that specific website. The image upload is done via an upload button on the website homepage at (big blue button that says UPLOAD IMAGES.Įvery time I upload a jpeg file to that website all file associations are changed for jpeg and psd documents. I have now discovered that as well as this issue being caused when dragging a file to the desktop, the same problem with file associations being changed happens when I upload an image to a website that I use. This does not happen when using OSX 10.12.5 Using fsevents I can see that when dragging the file to the desktop, a change is made to the (stored in Private/Var/Folder/51/xxxxxx/C folder) so I assume that this is responsible for the OSX file associations being changed.įirefox should not be overriding and permanently changing OSX file associations. Incidentally, it also causes the file association for Photoshop PSD files to change so Adobe Illustrator instead of Photoshop. File association now shows 'Open with: Preview.app'.īy dragging the file to the desktop from Firefox the file associations (for ALL jpg files) are changed to open in Apple Preview, overriding any saved settings in OSX.

Go to firefox, drag image (jpg) from a website to tge desktop. File association shows 'Open with: Photoshop.app' Select a JPG file on the desktop (OSX 10.10.5). Details User Agent: Mozilla/5.0 (Macintosh Intel Mac OS X 10.10 rv:58.0) Gecko/20100101 Firefox/58.0

My paintbrush app base bug