fix bug where correct date part choice wasn't detected on property panel creation
fix bug where correct date part choice wasn't detected on property panel creation

citation-style-language/csl-editor,citation-style-editor/csl-editor,citation-style-editor/csl-editor,citation-style-language/csl-editor,fbennett/csl-editor,citation-style-editor/csl-editor,adam3smith/csl-editor,adam3smith/csl-editor,adam3smith/csl-editor,citation-style-language/csl-editor,fbennett/csl-editor