#include "ofMain.h"
#include "ofApp.h"
#include "ofAppGLFWWindow.h"

int main() { 
    ofGLFWWindowSettings settings;
    settings.width = 1280;
    settings.height = 720;
    settings.setPosition(ofVec2f(300,0));
    settings.resizable = true;
    shared_ptr<ofAppBaseWindow> mainWindow = ofCreateWindow(settings);
    mainWindow->setFullscreen(true);
    
    settings.width = 500;
    settings.height = ofGetScreenHeight();
    settings.setPosition(ofVec2f(0,0));
    settings.shareContextWith = mainWindow;
    shared_ptr<ofAppBaseWindow> guiWindow = ofCreateWindow(settings);
    
    shared_ptr<ofApp> mainApp(new ofApp);
    mainApp->setupGui();
    ofAddListener(guiWindow->events().draw, mainApp.get(), &ofApp::drawGui);
    ofAddListener(guiWindow->events().keyPressed, mainApp.get(), &ofApp::guiKeyPressed);
    
    ofRunApp(mainWindow, mainApp);
    ofRunMainLoop();
}

#include "ofMain.h"
#include "ofApp.h"
#include "ofAppGLFWWindow.h"

int main() { 
    ofGLFWWindowSettings settings;
    settings.width = 1280;
    settings.height = 720;
    settings.setPosition(ofVec2f(300,0));
    settings.resizable = true;
    shared_ptr<ofAppBaseWindow> mainWindow = ofCreateWindow(settings);
    mainWindow->setFullscreen(true);
    
    settings.width = 500;
    settings.height = 900;
    settings.setPosition(ofVec2f(0,0));
    settings.shareContextWith = mainWindow;
    shared_ptr<ofAppBaseWindow> guiWindow = ofCreateWindow(settings);
    
    shared_ptr<ofApp> mainApp(new ofApp);
    mainApp->setupGui();
    ofAddListener(guiWindow->events().draw, mainApp.get(), &ofApp::drawGui);
    ofAddListener(guiWindow->events().keyPressed, mainApp.get(), &ofApp::guiKeyPressed);
    
    ofRunApp(mainWindow, mainApp);
    ofRunMainLoop();
}

--- 
+++ 
@@ -12,7 +12,7 @@
     mainWindow->setFullscreen(true);
     
     settings.width = 500;
-    settings.height = 900;
+    settings.height = ofGetScreenHeight();
     settings.setPosition(ofVec2f(0,0));
     settings.shareContextWith = mainWindow;
     shared_ptr<ofAppBaseWindow> guiWindow = ofCreateWindow(settings);
Make gui window a bit more responsive
