This design-time message occurs if the True or False resulting actions of the macro rules of the current DiaryGridLine includes has a large number of unchecked style options, as in the example below.
Suspiciously high number of un-checked options on the LEFT and a more likely scenario on the RIGHT where most options are set to neutral (don't care).
The settings on the left does not simply mean "add bold"; it means "add bold and remove non-breaking and remove italic and remove outline ... and remove subscript".
Meaning of the 3 checkbox settings in the Macros Reulting Actions options
Solution
If you want to ignore, leave unchanged, attributes, then the checkbox setting to use is the neutral one.
Topic 181995, last updated on 01-Aug-2020