The filter of the grid's "Filter by" quick action (spec §12.4, §8.5): Equal on the clicked cell's value, read as a value of the column's type, or Is Empty on a null cell. undefined when the type has no Equal (StrictTime, Variant and types Cube doesn't know) or the value doesn't read as one of the type. The cell is a JSON scalar as the engine returned it: a string is taken exactly (an integer or decimal stays exact text, a string isn't trimmed), a number through String(), and a timestamp loses its +0000.