A rounding error occasionally occurs here (found when using RectangleSelect), causing this method to unexpectedly return null, which in turn causes RectangleSelection.ReplaceSelectionWithText() to incorrectly set textArea.Caret.Position to (Line = 1, Column = 1).
Note that the epsilon value of 1e-12 is an estimation based on the accuracy of the visualTop value, which has 13 decimals when its integer value is in the thousands (4 digits).
A rounding error occasionally occurs here (found when using RectangleSelect), causing this method to unexpectedly return null, which in turn causes RectangleSelection.ReplaceSelectionWithText() to incorrectly set textArea.Caret.Position to (Line = 1, Column = 1).
Note that the epsilon value of 1e-12 is an estimation based on the accuracy of the visualTop value, which has 13 decimals when its integer value is in the thousands (4 digits).