MacOS – Preview Markup Options for Shape Fill

I've run into this with some forms, it's not always clear why (although in your case the DRM seems the likely culprit). The workaround for me has always been filling it out as normal, then using the print to PDF functionality (File → Print → PDF → Save as PDF). Certainly not the easiest, and it means you can't re-edit in some situations. But it's still better than dealing with Acrobat.

Alternatively, you could buy PDFPen, which is a pretty fool-proof way of dealing with any PDF form you can find.

To make Preview open PDFs in the "Two Pages" mode, go to Preferences --> PDF, then select the desired mode in the "Show as" menu.

There is no shortcut to go to "Almost Fullscreen Mode" by default, but you can create one:

• Go to System Preferences --> Keyboard --> Shortcuts;
• Click "App Shortcuts";
• Click the "+" button to add a new shortcut;
• You'll be asked for the menu title you want to link to a shortcut. For the command you want, it is "Zoom";
• You will also be able to specify whether you want the shortcut to be available in all application or a specific application only.

EDIT: Here's an AppleScript solution to set the first window of Preview (the frontmost opened document of Preview) to the size of the screen (works only with one display connected):

tell application "Preview"
    tell application "Finder" to set screen_resolution to bounds of window of desktop
    set bounds of window 1 to screen_resolution
end tell