With System 7.0, you can drag a document icon onto the creator application's icon, which will open the document into the application. This is called drop-launching
MacDraw Pro 1.5 will drop launch native files from MacDraw Pro 1.0/1.5 (document and palette files) and any file that will be opened using an XTND filter. PICT files from other applications and MacDraw 1.9 files will not drop launch.
MacDraw Pro 1.0 v1 will "drop-launch" only its own native files, even though it has translators to other type of files.
If files do not drop-launch correctly after installing MacDraw Pro 1.5, rebuild the desktop on the hard drive.