Fix upload dialog to include 'All Supported Formats' instead of separating them

Core/FormBrowser.cs

@@ -84,6 +84,7 @@ public FormBrowser(UpdaterSettings updaterSettings){
             this.notification.Show();
 
             this.browser = new ChromiumWebBrowser("https://tweetdeck.twitter.com/"){
+                DialogHandler = new FileDialogHandler(),
                 MenuHandler = new ContextMenuBrowser(this),
                 JsDialogHandler = new JavaScriptDialogHandler(),
                 KeyboardHandler = new KeyboardHandlerBrowser(this),

Core/Handling/General/FileDialogHandler.cs

@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Windows.Forms;
+using CefSharp;
+
+namespace TweetDuck.Core.Handling.General{
+    sealed class FileDialogHandler : IDialogHandler{
+        public bool OnFileDialog(IWebBrowser browserControl, IBrowser browser, CefFileDialogMode mode, string title, string defaultFilePath, List<string> acceptFilters, int selectedAcceptFilter, IFileDialogCallback callback){
+            CefFileDialogMode dialogType = mode & CefFileDialogMode.TypeMask;
+
+            if (dialogType == CefFileDialogMode.Open || dialogType == CefFileDialogMode.OpenMultiple){
+                string allFilters = string.Join(";", acceptFilters.Select(filter => "*"+filter));
+
+                using(OpenFileDialog dialog = new OpenFileDialog{
+                    AutoUpgradeEnabled = true,
+                    DereferenceLinks = true,
+                    Multiselect = dialogType == CefFileDialogMode.OpenMultiple,
+                    Title = "Open Files",
+                    Filter = $"All Supported Formats ({allFilters})|{allFilters}|All Files (*.*)|*.*"
+                }){
+                    if (dialog.ShowDialog() == DialogResult.OK){
+                        callback.Continue(acceptFilters.FindIndex(filter => filter == Path.GetExtension(dialog.FileName)), dialog.FileNames.ToList());
+                    }
+                    else{
+                        callback.Cancel();
+                    }
+
+                    callback.Dispose();
+                }
+
+                return true;
+            }
+            else{
+                callback.Dispose();
+                return false;
+            }
+        }
+    }
+}

TweetDuck.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="packages\CefSharp.WinForms.57.0.0\build\CefSharp.WinForms.props" Condition="Exists('packages\CefSharp.WinForms.57.0.0\build\CefSharp.WinForms.props')" />
   <Import Project="packages\CefSharp.Common.57.0.0\build\CefSharp.Common.props" Condition="Exists('packages\CefSharp.Common.57.0.0\build\CefSharp.Common.props')" />
@@ -97,6 +97,7 @@
     <Compile Include="Core\FormBrowser.Designer.cs">
       <DependentUpon>FormBrowser.cs</DependentUpon>
     </Compile>
+    <Compile Include="Core\Handling\General\FileDialogHandler.cs" />
     <Compile Include="Core\Handling\KeyboardHandlerBrowser.cs" />
     <Compile Include="Core\Handling\KeyboardHandlerNotification.cs" />
     <Compile Include="Core\Handling\RequestHandlerBrowser.cs" />