From ef1f12201f4e871b5d042151a35438b0955e1fd2 Mon Sep 17 00:00:00 2001
From: Hedongliang Liu <uniquelhdl@gmail.com>
Date: Wed, 20 Aug 2025 16:58:13 +0200
Subject: [PATCH] implemented showsubsectionsatfirstoverview option

---
 CELbeamer.cls    | 11 ++++++++++-
 CHANGELOG.md     |  2 +-
 README.md        |  4 ++++
 presentation.tex |  4 ++--
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/CELbeamer.cls b/CELbeamer.cls
index 26cddff..dfb3e6b 100644
--- a/CELbeamer.cls
+++ b/CELbeamer.cls
@@ -26,6 +26,8 @@
 \overviewatsectionfalse
 \newif\ifshowallatfirstoverview
 \showallatfirstoverviewtrue
+\newif\ifshowsubsectionsatfirstoverview
+\showsubsectionsatfirstoverviewfalse
 
 \def\groupname#1{\def\@groupname{#1}}
 \def\groupnamewidth#1{\def\@groupnamewidth{#1}}
@@ -62,6 +64,9 @@
 \DeclareOption{overviewatsection}{
   \overviewatsectiontrue
 }
+\DeclareOption{showsubsectionsatfirstoverview}{
+  \showsubsectionsatfirstoverviewtrue
+}
 
 \ExecuteOptions{en,bigfoot,helvet}
 
@@ -663,7 +668,11 @@
 \ifnum\value{section}=1
 {
   \begin{frame}[tableofcontents=blue]{Overview}
-    \tableofcontents[subsectionstyle=show/show/hide]
+    \ifshowsubsectionsatfirstoverview{
+      \tableofcontents
+    }
+    \else{\tableofcontents[subsectionstyle=show/show/hide]}
+    \fi 
   \end{frame}
 }
 \else
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7889591..65e6cd3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,4 +13,4 @@ All changes of this template is documented in this file.
 - Added the group logo onto overview page
 - Changed the normal fontsize to 19pt
 - Added the spaceforface option to leave space on the right for recording
-- Added the overviewatsection option
\ No newline at end of file
+- Added the overviewatsection, showsubsectionsatfirstoverview option
\ No newline at end of file
diff --git a/README.md b/README.md
index 6a5871d..84c22bb 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,8 @@ E.g., `\only<2|handout:0>{This is not shown in handout mode.}`, `\item<1-|handou
 
 - The `overviewatsection` option displays the table of contents at each section. Only subsections of the current section is shown.
 
+- The `showsubsectionsatfirstoverview` option shows all the subsections at the first overview. This requires `overviewatsection` option.
+
 Example: `\documentclass[de, navbaron, kitgrid, handout, overviewatsection]{CELbeamer}`
 
 ## Title Slide
@@ -64,8 +66,10 @@ Additionally, for horizontal layouts, you can choose the color of the KIT logo.
 Example: `\begin{frame}[title white horizontal, picture=images/palladio_bauplan, kitlogo=black]`
 
 ## Special Slides
+### Table of content
 For tables of contents, you can specify the option `tableofcontents=<color>`, where `color` can be either `blue` or `green`. The table of contents will then be shown on a fully colored slide.
 
+### Image slides
 There are also special layouts for divider slides with large images. You can select them using frame options.
 
 | Vertical image share: | Frame Option                   |
diff --git a/presentation.tex b/presentation.tex
index 64b0194..2806521 100644
--- a/presentation.tex
+++ b/presentation.tex
@@ -4,10 +4,10 @@
 %% Modified by: Hedongliang Liu
 %% Last modified on: 14.08.2025
 %%%%%%%%%%% CEL beamer class %%%%%%%%%%%%%%%
-\documentclass[handout, overviewatsection]{CELbeamer} 
+\documentclass[handout, overviewatsection, showsubsectionsatfirstoverview]{CELbeamer} 
 %% default options: en, helvet, bigfoot (12pt)
 %% other options: de, franklin, smallfoot (11pt), navbaron, kitgrid, handout, 
-%% spaceforface, overviewatsection
+%% spaceforface, overviewatsection, showsubsectionsatfirstoverview
 
 %%%%%%%%%%% Load packages (from previous CEL template %%%%%%%%%%%%%%%
 \newcommand{\templates}{packages}