Solution Define all columns to be fixed,
setting the option fixedColumns=:
GuiXT
Table (3,6) (9,80) name="cust" rows="12" fixedColumns="3"
Column "Company" size=30 name="company"
Column "City" size=20 name="city"
Column "Country" size=20 name="country"

Without option fixedColumns=:
GuiXT
Table (3,6) (9,80) name="cust" rows="12"
Column "Company" size=30 name="company"
Column "City" size=20 name="city"
Column "Country" size=20 name="country"

With fixedColumns= "1":
GuiXT
Table (3,6) (9,80) name="cust" rows="12" fixedColumns="1"
Column "Company" size=30 name="company"
Column "City" size=20 name="city"
Column "Country" size=20 name="country"

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