Added scrolling over tabs with wheel to switch channels.

src/widgets/helper/NotebookTab.cpp

@@ -479,6 +479,20 @@ void NotebookTab::mouseMoveEvent(QMouseEvent *event)
     Button::mouseMoveEvent(event);
 }
 
+void NotebookTab::wheelEvent(QWheelEvent *event)
+{
+    float mouseMultiplier = getSettings()->mouseScrollMultiplier;
+    wheelValue += event->delta() * mouseMultiplier;
+
+    if (wheelValue > WHEEL_STEP) {
+        this->notebook_->selectNextTab();
+        wheelValue = 0;
+    } else if (wheelValue < -WHEEL_STEP) {
+        this->notebook_->selectPreviousTab();
+        wheelValue = 0;
+    }
+}
+
 QRect NotebookTab::getXRect()
 {
     //    if (!this->notebook->getAllowUserTabManagement()) {

src/widgets/helper/NotebookTab.hpp

@@ -12,6 +12,7 @@
 namespace chatterino {
 
 #define NOTEBOOK_TAB_HEIGHT 28
+#define WHEEL_STEP 240
 
 // class Notebook;
 class Notebook;
@@ -61,6 +62,7 @@ protected:
     virtual void dragEnterEvent(QDragEnterEvent *event) override;
 
     virtual void mouseMoveEvent(QMouseEvent *event) override;
+    virtual void wheelEvent(QWheelEvent *event) override;
 
 private:
     bool hasXButton();
@@ -83,6 +85,8 @@ private:
     bool mouseOverX_ = false;
     bool mouseDownX_ = false;
 
+    float wheelValue = 0;
+
     HighlightState highlightState_ = HighlightState::None;
     bool highlightEnabled_ = true;
     QAction *highlightNewMessagesAction_;