From 23a56170607e6c47bbe9b96c3d35cc979bea44a8 Mon Sep 17 00:00:00 2001
From: Christian Heinemann <heinemann.christian@gmail.com>
Date: Fri, 3 Jul 2026 17:13:46 +0200
Subject: [PATCH] Auto-focus parameter filter on typing

Focus the filter input in the simulation parameters window as soon as
the user starts typing, without having to click the field first.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 source/Gui/SimulationParametersMainWindow.cpp | 16 ++++++++++++++++
 source/Gui/SimulationParametersMainWindow.h   |  2 ++
 2 files changed, 18 insertions(+)

diff --git a/source/Gui/SimulationParametersMainWindow.cpp b/source/Gui/SimulationParametersMainWindow.cpp
index b424bd2b77..13b36f9ddc 100644
--- a/source/Gui/SimulationParametersMainWindow.cpp
+++ b/source/Gui/SimulationParametersMainWindow.cpp
@@ -258,6 +258,9 @@ void SimulationParametersMainWindow::processDetailWidget()
             //AlienGui::ResetFilterText();
 
             ImGui::Spacing();
+            if (shouldStartFilterTyping()) {
+                ImGui::SetKeyboardFocusHere();
+            }
             AlienGui::InputFilter(AlienGui::InputFilterParameters().width(250.0f), _filter);
         }
         AlienGui::EndTreeNode();
@@ -271,6 +274,19 @@ void SimulationParametersMainWindow::processDetailWidget()
     }
 }
 
+bool SimulationParametersMainWindow::shouldStartFilterTyping() const
+{
+    if (ImGui::IsAnyItemActive() || !ImGui::IsWindowFocused(ImGuiFocusedFlags_RootAndChildWindows)) {
+        return false;
+    }
+    for (auto const& c : ImGui::GetIO().InputQueueCharacters) {
+        if (c >= 32 && c != 127) {
+            return true;
+        }
+    }
+    return false;
+}
+
 void SimulationParametersMainWindow::processExpertWidget()
 {
     if (ImGui::BeginChild("##expert", {0, 0})) {
diff --git a/source/Gui/SimulationParametersMainWindow.h b/source/Gui/SimulationParametersMainWindow.h
index 1d72bb2aaf..1ad954210d 100644
--- a/source/Gui/SimulationParametersMainWindow.h
+++ b/source/Gui/SimulationParametersMainWindow.h
@@ -26,6 +26,8 @@ class SimulationParametersMainWindow : public AlienWindow
     void processExpertWidget();
     void processStatusBar();
 
+    bool shouldStartFilterTyping() const;
+
     struct Location
     {
         std::string name;