While this does not allow you to suppress them, coding something like:
B4X:
'Making all colors white has effect of producing a blank screen
'instead of spinning circles when loading etc
PassedPage.SetLoaderHEARTBEAT(ABM.COLOR_WHITE, ABM.INTENSITY_NORMAL, ABM.COLOR_WHITE, ABM.INTENSITY_NORMAL, ABM.COLOR_WHITE, ABM.INTENSITY_NORMAL, ABM.COLOR_WHITE, ABM.INTENSITY_NORMAL)
For these to work properly, you need to place them in the "BuildPage" sub routine.
I am using custom components exclusively - there is no "BuildPage" - however I found that if the above code is placed in the ABMComp_Build sub then it works.