CustomSplitViewController: override primary controller's horizontal size class when expanded

1 files changed, 14 insertions, 0 deletions

diff --git a/ios/MullvadVPN/CustomSplitViewController.swift b/ios/MullvadVPN/CustomSplitViewController.swift
index 557c2f23d7..ecd0d30dff 100644
--- a/ios/MullvadVPN/CustomSplitViewController.swift
+++ b/ios/MullvadVPN/CustomSplitViewController.swift
@@ -54,4 +54,18 @@ class CustomSplitViewController: UISplitViewController, RootContainment {
         dividerView?.backgroundColor = dividerColor
     }
 
+    override func overrideTraitCollection(forChild childViewController: UIViewController) -> UITraitCollection? {
+        guard let traitCollection = super.overrideTraitCollection(forChild: childViewController) else { return nil }
+
+        // Pass the split controller's horizontal size class to the primary controller when split
+        // view is expanded.
+        if !self.isCollapsed, childViewController == self.viewControllers.last {
+            let sizeOverrideTraitCollection = UITraitCollection(horizontalSizeClass: self.traitCollection.horizontalSizeClass)
+
+            return UITraitCollection(traitsFrom: [traitCollection, sizeOverrideTraitCollection])
+        } else {
+            return traitCollection
+        }
+    }
+
 }