diff --git a/include/AModule.hpp b/include/AModule.hpp
index 2ffc429c..2fcbfc23 100644
--- a/include/AModule.hpp
+++ b/include/AModule.hpp
@@ -36,6 +36,7 @@ class AModule : public IModule {
   SCROLL_DIR getScrollDir(GdkEventScroll *e);
   bool tooltipEnabled() const;
 
+  std::vector<int> pid_children_;
   const std::string name_;
   const Json::Value &config_;
   Gtk::EventBox event_box_;
@@ -54,7 +55,6 @@ class AModule : public IModule {
   const bool isTooltip;
   const bool isExpand;
   bool hasUserEvents_;
-  std::vector<int> pid_;
   gdouble distance_scrolled_y_;
   gdouble distance_scrolled_x_;
   std::map<std::string, std::string> eventActionMap_;
diff --git a/src/AModule.cpp b/src/AModule.cpp
index 7de1ad9a..259c6a39 100644
--- a/src/AModule.cpp
+++ b/src/AModule.cpp
@@ -83,7 +83,7 @@ AModule::AModule(const Json::Value& config, const std::string& name, const std::
 }
 
 AModule::~AModule() {
-  for (const auto& pid : pid_) {
+  for (const auto& pid : pid_children_) {
     if (pid != -1) {
       killpg(pid, SIGTERM);
     }
@@ -93,7 +93,7 @@ AModule::~AModule() {
 auto AModule::update() -> void {
   // Run user-provided update handler if configured
   if (config_["on-update"].isString()) {
-    pid_.push_back(util::command::forkExec(config_["on-update"].asString()));
+    pid_children_.push_back(util::command::forkExec(config_["on-update"].asString()));
   }
 }
 // Get mapping between event name and module action name
@@ -182,7 +182,7 @@ bool AModule::handleUserEvent(GdkEventButton* const& e) {
       format.clear();
   }
   if (!format.empty()) {
-    pid_.push_back(util::command::forkExec(format));
+    pid_children_.push_back(util::command::forkExec(format));
   }
   dp.emit();
   return true;
@@ -267,7 +267,7 @@ bool AModule::handleScroll(GdkEventScroll* e) {
   this->AModule::doAction(eventName);
   // Second call user scripts
   if (config_[eventName].isString())
-    pid_.push_back(util::command::forkExec(config_[eventName].asString()));
+    pid_children_.push_back(util::command::forkExec(config_[eventName].asString()));
 
   dp.emit();
   return true;
diff --git a/src/modules/custom.cpp b/src/modules/custom.cpp
index 052247e0..0220e348 100644
--- a/src/modules/custom.cpp
+++ b/src/modules/custom.cpp
@@ -35,6 +35,13 @@ waybar::modules::Custom::~Custom() {
 
 void waybar::modules::Custom::delayWorker() {
   thread_ = [this] {
+    for (int i: this->pid_children_) {
+      int status;
+      waitpid(i, &status, 0);
+    }
+
+    this->pid_children_.clear();
+
     bool can_update = true;
     if (config_["exec-if"].isString()) {
       output_ = util::command::execNoRead(config_["exec-if"].asString());