please tell the brains what version of FM you're using, along with platform (OS) and version. That'll help.
I would suggest you take a look at the background color of the Layout itself. It has a background that is separate from the Body element (or any of the other elements). I would guess that FileMaker's rendering engine is briefly showing you the layout background and it scrolls and renders the body background on top of it.
Sorry David ....im using filmmaker 11 on windows 10
I tried what you suggested... I opened all the parts on the layout and applied the same color... no difference.
Given that combination of windows and filemaker, there may be an issue with your windows display settings.
bring up the windows display settings and check to see if it's set at 100% or not. Given windows 10, you may have to dig a bit to pull up the precise percentage.
There are known display issues that occur with several versions of FileMaker and windows 7 - 10 if the display is not kept at 100%.
Phil makes a good observation (as always). But you said "opened all the parts on the layout..." which doesn't quite sound like what I was trying to communicate, so I wanted to clarify a bit further. Here are some (hopefully) helpful images showing what I mean. You, of course, would want to use your blue color instead of the garish ones I chose for this demonstration.
Giving the layout background it's own color you wouldn't ever be able to see unless you gave your other Layout parts a background of None or Transparent. Or, as I'm guessing in your case, when you are scrolling the layout and the FM rendering engine is slow at updating the full page.
Can you replicate the behavior in a new file? If yes, upload it here and we can take a look at it.
Thank you Justin
I upgraded the file to FM 15 and the flashing disappeared. In the FM 11 version, the list view the body part text blocks were set to "engraved" and I think this may have put pressure on the rendering ( and I do have as issue with memory on my machine
Thank you so much for your help.