Minor enhancement & cleanup & fix

• a bit of cleanup after deleting sample designer
• eliminate side effects on sample selection list panel visibility when document was modified
• allow sample creation even if sample list is not visible (important for single-sample mode)

added GUI cleanup enhancement labels

requested review from @j.wuttke

changed title from Nv17 to Minor anhancement & cleanup & fix

changed title from Minor anhancement & cleanup & fix to Minor enhancement & cleanup & fix

ok

approved this merge request

merged

mentioned in commit a8390199