diff --git a/Source/Modules/ControllerModules/ctlInputMethod_HandleDisplay.swift b/Source/Modules/ControllerModules/ctlInputMethod_HandleDisplay.swift
index 40e49585..3f50bba0 100644
--- a/Source/Modules/ControllerModules/ctlInputMethod_HandleDisplay.swift
+++ b/Source/Modules/ControllerModules/ctlInputMethod_HandleDisplay.swift
@@ -33,7 +33,7 @@ extension ctlInputMethod {
         x: lineHeightRect.origin.x + lineHeightRect.size.width + 5, y: lineHeightRect.origin.y
       )
     }
-    var tooltipContentDirection: NSAttributedTextView.writingDirection = {
+    let tooltipContentDirection: NSAttributedTextView.writingDirection = {
       if mgrPrefs.alwaysShowTooltipTextsHorizontally { return .horizontal }
       return isVerticalTyping ? .vertical : .horizontal
     }()
diff --git a/Source/Modules/UIModules/TooltipUI/ctlTooltip.swift b/Source/Modules/UIModules/TooltipUI/ctlTooltip.swift
index 6adbee54..cd8fb857 100644
--- a/Source/Modules/UIModules/TooltipUI/ctlTooltip.swift
+++ b/Source/Modules/UIModules/TooltipUI/ctlTooltip.swift
@@ -28,6 +28,7 @@ public class ctlTooltip: NSWindowController {
 
   public var direction: NSAttributedTextView.writingDirection = .horizontal {
     didSet {
+      if #unavailable(macOS 10.13) { direction = .horizontal }
       messageText.direction = direction
     }
   }
@@ -59,7 +60,6 @@ public class ctlTooltip: NSWindowController {
     direction: NSAttributedTextView.writingDirection = .horizontal
   ) {
     self.direction = direction
-    messageText.direction = self.direction
     self.tooltip = tooltip
     window?.orderFront(nil)
     set(windowTopLeftPoint: point, bottomOutOfScreenAdjustmentHeight: heightDelta)