While you're on the View menu, try

View > Zoom > Reset

in case you are accidentally triggering the zoom feature when scrolling (Ctrl+mousewheel zooms up and down).

thanks for your help. that did help. how can i lock in to that type size so it doesn't keep happening?

Do you think it's the mouse wheel? You can set the wheel to do something else to avoid accidental zooming, but this take a couple of minutes.

To edit or reset your mouse wheel actions, you can use the about:config preferences pane. (Please note that an add-on or system-level control panel applet might be able to override these settings, so if these don't work, you could check there.)

(1) Type or paste about:config in the address bar and press Enter (click the button promising to be careful, and please do be careful!)

(2) In the filter box, type or paste wheel and pause until the preferences are filtered

Now you can reset any changed preferences (shown in bold) to their defaults, or you can change them to suit your preferences. The names can be hard to pick out, but here is what you should see:

Wheel alone - Normal scrolling

• Name = mousewheel.withnokey.action
• Default = 0 (scroll)
• Scroll default = 6 lines (Name = mousewheel.withnokey.numlines)

Alt+Wheel - Fine Scrolling

• Name = mousewheel.withaltkey.action
• Default = 0 (scroll)
• Scroll default = 1 lines (Name = mousewheel.withaltkey.numlines)

Ctrl+Wheel - Zoom

• Name = mousewheel.withcontrolkey.action
• Default = 3 (zoom text)
• To disable: change to match one of the actions you like better (e.g., 0 for normal scrolling)

Shift+Wheel - Back/Forward

• Name = mousewheel.withshiftkey.action
• Default = 2 (Back / Forward in history)
• My Recommendation: change to 1 (page up / page down)

thank you for this. i have to have my coffee before i try this one! made a copy for my file. appreciate your help.