re : the lines are so scrunched up together that it's impossible to read.

Are you talking about the Message List - the list of emails below the column headers ?

try changing the Density: Via Menu app icon: Menu app icon > Density > offers three options -Compact, Default, Relaxed

OR via the 'Menu Bar' toolbar: 'View' > 'Density' > offers three options -Compact, Default, Relaxed

Thanks--yes, I finally found the density control. That helps some, but I am still confused sometimes because the control buttons are also in all different places now. I appreciate your reply.

The 'Menu Bar' toolbar - File, Edit, View, go, etc is still available. Use the 'Menu App' icon (has 2 lines shown on far right)

• Menu app icon > View > Toolbars - select 'Menu Bar'

The old 'Mail Toolbar' has gone and it has been replaced with the 'Unified Toolbar'. You can Customise the Unified toolbar eg: Put 'Write' and 'Tag' on it.

• Right click on 'Unified Toolbar' - it has the Global Search CTRL+K on it - and select 'Customise'
• After dragging items you want onto the toolbar, select the 'Button Style' you want and click on 'Save'

Some helpful info:

• https://support.mozilla.org/en-US/kb/unified-toolbar