
766 So.2d 417 (2000)
Joe LOWERY, Appellant,
v.
STATE of Florida, Appellee.
No. 4D00-1617.
District Court of Appeal of Florida, Fourth District.
August 23, 2000.
Joe Lowery, Immokalee, pro se.
Robert A. Butterworth, Attorney General, Tallahassee, and Jeanine M. Germanowicz, Assistant Attorney General, West Palm Beach, for appellee.
PER CURIAM.
Appellant Joe Lowery seeks review of an order summarily denying his motion for post-conviction relief filed pursuant to rule 3.850, Florida Rules of Criminal Procedure. Appellant's motion purports to challenge his habitual felony offender sentence following his guilty plea and adjudication for delivery of cocaine, but his claim is directed to gain-time entitlement. His offense occurred during the window period of Heggs v. State, 759 So.2d 620 (Fla.2000), which he cites as the basis of his challenge.
The trial court summarily denied relief on the grounds that appellant did not fall within the window period. We disagree, but affirm nonetheless for different reasons. This court may affirm a trial court decision deemed "right for a different reason" under the "tipsy coachman" rule acknowledged as far back as Carraway v. Armour & Co., 156 So.2d 494 (Fla.1963).
We affirm the summary denial of post-conviction relief in this case because appellant's gain-time challenge must first be entertained in the Department of Corrections. If the appellant is not satisfied with its ruling, then he can file a petition for writ of mandamus with the appropriate circuit court. See Clements v. State, 761 So.2d 1245 (Fla. 2d DCA 2000).
AFFIRMED.
STEVENSON, SHAHOOD and HAZOURI, JJ., concur.
