Still working on inventory UI, still a bit glitchy

Scripts/Inventory UI.gd

@@ -8,11 +8,11 @@ func _ready():
 	updateUI()
 
 func updateUI():
-
-		
+	if firstIndex >= inventory.get_item_count() and firstIndex != 0:
+		firstIndex = firstIndex - 5
 	var i = 0
 	while i < 5:
-		if i < inventory.get_item_count():
+		if firstIndex + i < inventory.get_item_count():
 			items[i].set_disabled(false)
 			items[i].set_button_icon(inventory.get_item_icon(firstIndex + i))
 			items[i].set_tooltip(inventory.get_item_text(firstIndex+i))
@@ -28,7 +28,17 @@ func updateUI():
 		#set index?
 	print("Updated inventory UI")
 		
-		
+func _on_Inventory_right_pressed():
+	if (inventory.get_item_count() > firstIndex + 5):
+		firstIndex = firstIndex + 5
+	updateUI()
+
+
+func _on_Inventory_left_pressed():
+	if firstIndex != 0:
+		firstIndex = firstIndex - 5
+	updateUI()
+
 func disableRest(num):
 	var j = 0
 	while j < 5:
@@ -84,15 +94,3 @@ func _on_5_toggled(button_pressed):
 		enableRest()
 		inventory.unselect_all()
 	print(inventory.get_selected_items())
-
-
-func _on_Inventory_right_pressed():
-	if (inventory.get_item_count() > firstIndex + 4):
-		firstIndex = firstIndex + 5
-	updateUI()
-
-
-func _on_Inventory_left_pressed():
-	if firstIndex != 0:
-		firstIndex = firstIndex - 5
-	updateUI()

assets/Fonts/Be Vietnam.tres

@@ -3,5 +3,5 @@
 [ext_resource path="res://assets/Fonts/BeVietnamPro-Medium.ttf" type="DynamicFontData" id=1]
 
 [resource]
-size = 12
+size = 15
 font_data = ExtResource( 1 )