In the new Java Control panel, when you go to manage certificates / user / Signer CA / import, the file choser dialog shown has dropdown where the only entry is "Certificate files", and this filter (if it works) does not show ".p12" files.
Unlike the Swing based version, there is no "All Files" option to pick from any file, so there is no way to find and select my "certs.p12" file I have in the selected directory