Scrolling unavailable in the browser
On Ubuntu-Mate 18.04.1 with gThumb 3.6.1, inside the browser view, when one picture is selected the scrolling has a weird behaviour. If scrolling, pictures begin to scroll and few second after the picture selected come back in the window of the browser view. So it results that it is impossible to scroll over of the pictures inside the folder.
In other hand, when you enter in a folder and not select a picture, the scrolling function works.