diff -r 08dc62e03a6d -r c6114b3af3a6 src/settingseditor/settingseditor.cpp
--- a/src/settingseditor/settingseditor.cpp	Sun Feb 02 00:50:57 2020 +0200
+++ b/src/settingseditor/settingseditor.cpp	Sun Feb 02 00:51:06 2020 +0200
@@ -40,6 +40,7 @@
 	this->settings->setLocale(this->ui.language->currentData().toString());
 	this->settings->setMainColor(this->ui.mainColorButton->selectedColor());
 	this->settings->setBackgroundColor(this->ui.backgroundColorButton->selectedColor());
+	this->settings->setLineThickness(static_cast<GLfloat>(this->ui.lineThickness->value()));
 	this->librariesEditor.saveSettings(this->settings);
 }
 
@@ -70,6 +71,7 @@
 	this->setCurrentLanguage(this->settings->locale());
 	this->ui.mainColorButton->setSelectedColor(this->settings->mainColor());
 	this->ui.backgroundColorButton->setSelectedColor(this->settings->backgroundColor());
+	this->ui.lineThickness->setValue(static_cast<double>(this->settings->lineThickness()));
 }
 
 void SettingsEditor::setCurrentLanguage(const QString& localeCode)