8 files declare their use of GridStackManagerInterface in GridStack 8

GridStackAdmin.php in src/Form/GridStackAdmin.php

GridStackEntityFormatterBase.php in src/Plugin/Field/FieldFormatter/GridStackEntityFormatterBase.php

GridStackFileFormatterBase.php in src/Plugin/Field/FieldFormatter/GridStackFileFormatterBase.php

GridStackForm.php in modules/gridstack_ui/src/Form/GridStackForm.php

GridStackLayout.php in src/Layout/GridStackLayout.php

GridStackLayoutDeprecated.php in src/Layout/GridStackLayoutDeprecated.php

GridStackListBuilder.php in modules/gridstack_ui/src/Controller/GridStackListBuilder.php

GridStackViews.php in src/Plugin/views/style/GridStackViews.php