diff --git a/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
index 1ee5cc5cc5..ea4254fac4 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
@@ -22,7 +22,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 {
 	public class AssetBrowserLogic : ChromeLogic
 	{
-		static string[] allowedExtensions;
+		readonly string[] allowedExtensions;
+		readonly IEnumerable<IReadOnlyPackage> acceptablePackages;
 
 		readonly World world;
 
@@ -50,7 +51,6 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			this.world = world;
 
 			panel = widget;
-			assetSource = Game.ModData.ModFiles.MountedPackages.First();
 
 			var ticker = panel.GetOrNull<LogicTickerWidget>("ANIMATION_TICKER");
 			if (ticker != null)
@@ -217,6 +217,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			else
 				allowedExtensions = new string[0];
 
+			acceptablePackages = Game.ModData.ModFiles.MountedPackages.Where(p =>
+				p.Contents.Any(c => allowedExtensions.Contains(Path.GetExtension(c).ToLowerInvariant())));
+
 			assetList = panel.Get<ScrollPanelWidget>("ASSET_LIST");
 			template = panel.Get<ScrollItemWidget>("ASSET_TEMPLATE");
 			PopulateAssetList();
@@ -343,9 +346,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				return item;
 			};
 
-			// TODO: Re-enable "All Packages" once list generation is done in a background thread
-			// var sources = new[] { (IPackage)null }.Concat(GlobalFileSystem.MountedFolders);
-			var sources = Game.ModData.ModFiles.MountedPackages;
+			var sources = new[] { (IReadOnlyPackage)null }.Concat(acceptablePackages);
 			dropdown.ShowDropDown("LABEL_DROPDOWN_TEMPLATE", 280, sources, setupItem);
 			return true;
 		}
@@ -355,14 +356,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			assetList.RemoveChildren();
 			availableShps.Clear();
 
-			// TODO: This is too slow to run in the main thread
-			// var files = AssetSource != null ? AssetSource.AllFileNames() :
-			// GlobalFileSystem.MountedFolders.SelectMany(f => f.AllFileNames());
-			if (assetSource == null)
-				return;
-
-			var files = assetSource.Contents.OrderBy(s => s);
-			foreach (var file in files)
+			var files = assetSource != null ? assetSource.Contents : Game.ModData.ModFiles.MountedPackages.SelectMany(f => f.Contents).Distinct();
+			foreach (var file in files.OrderBy(s => s))
 			{
 				if (allowedExtensions.Any(ext => file.EndsWith(ext, true, CultureInfo.InvariantCulture)))
 				{