Feature request: TUI feature to set `prefer` at the currently observed path

[AleXoundOS]

For example, I wanted to see paths which a file shares data with when its represented size is 0 (visible using --expert mode). Relaunching btdu with --prefer=FOLDER_WITH_FILE option does the job: btdu shows shared data files, because now the file is represented in the preferred path. However, it's quite tedious to copy the path I'm interested in, paste into command line and launch again...