NAV CAL - Boolean Yes / No vs True / False

Boolean type can accept Yes/No and True/False values.
However, if Yes/No is used, it must be explicitly called.

Eg.

This Works
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BooleanTest := True

If BooleanTest THEN
 Message ('true!');
----------------------------------

This does not work
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BooleanTest := Yes

If BooleanTest THEN
 Message ('true!');
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This works
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BooleanTest := Yes

If BooleanTest = TRUE THEN
 Message ('true!');
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