Because the "Show tracks on map" option is related more closely to the list of GPX files loaded, I would suggest to relocate it just below the listing element. At the current position it is sitting between the two options regarding interpolation and therefore disturbing their unity. Reproducible: Always
What's about this file using digiKam AppImage bundle 5.4.0 pre release given at this url : https://drive.google.com/drive/folders/0BzeiVr-byqt5Y0tIRWVWelRJenM Gilles Caulier
Great, exactly as I assumed.