When open a PDF file, the name of the file shown in the PDF browser is different from the File name.
A PDF can be configured to show either the "File Name" or "Document Title" in the title bar. When the title is different from your File Name, it is very likely that you have set your display to "Document Title".
Note: This setting is only available in Gaaiho PDF Suite, not Gaaiho PDF Reader.
- Go to "File" > "Properties" > "Description" > "More Properties"
- select "Initial View", under "Display" choose "File Name"
This way, the name in the title bar will display the File Name.