What files should appear when selecting 'Opne'

Hi, For all previous versions of MuseScore, when one selected the 'Open' icon to select which files to work on or play back, only the MuseScore files would appear as expected. Now for some reason, an additional set of files, that have what appears to be a PDF icon also appears. The names in these files are the same as the Musescore ones and they start with a 'dot'. The appearance of these extra files make it inconvenient to find the file one is searching. These extra files never appeared before. This might not be a MuseScore problem - but rather an operating system one, but if you are able to help me hide these files so that they never appear, always like it used to be I would be grateful. It is possible to hide them by selecting Musescore files from the drop down menu above the 'Open' and 'Cancel' tabs at the bottom right, but you have to do this every time you want to open a file.

Thanks,

Henry