Revert "Small checks added; removed delayed texture refresh (no need for it)"

This reverts commit 640e43bd83a8e0ab9d351e172b46021cc4809a12.
Revert "Revert "Small checks added; removed delayed texture refresh (no need for it)""

This reverts commit a5e453383a06b48b7b784960f08400e3580e9ad2.
Revert "Check if the desired file selected in config dialog is valid no matter if we use extents or not"

This reverts commit 4385395d3779659fe00ee5864d7780de2d5999f6.