PyCharm CSS editing

Can you help me with one thing? Maybe I'm doing it wrong, but when I externalize my css definitions to a css file, and I try to add new entries, I cannot autocomplete for the classes/ids for which that css file is being used for. Do i need to set something up? The autocomplete works fine if the css is embedded directly into the HTML file in a <style> tag, but when it's externalized, the autocomplete only sees things declared within that file. Woudn't it be helpful to autocomplete for classes/ids that are not already in the css file but are linked through an HTML page in the project?