Using LibreOffice Calc 4.2.5.2 and WIndows 8.1 64-bit US
If you have a CSV file opened and try to open another CSV file, the CSV import prompt window does not appear automatically. In order to see the prompt, you have to select the Calc instance that’s already running from the Windows taskbar. This is further complicated when you have several CSV files opened in different Calc instances, because they you have to click on all of them to figure out which one will have the import prompt for the new file.
Dialogs and prompts in Windows should appear without the user having to select the program from the taskbar first, so I consider this a bug.