templates not working

i’m trying to change the output of different posts based on some custom fields. therefore i’ve generated gridster-templates/gridster-default.php in my theme folder but it seems not to be used.
it’s also very strange that even if i make some changes to views/gridster-default.php in the plugin folder i don’t recieve any changes.
do i have to tell gridster to use templates somehow?

thx in advance
Stefan

https://www.ads-software.com/plugins/cbach-wp-gridster/