diff --git a/FrameGrabber.cpp b/FrameGrabber.cpp
index d0c6cb7..69fcae7 100644
--- a/FrameGrabber.cpp
+++ b/FrameGrabber.cpp
@@ -305,7 +305,7 @@ void FrameGrabber::addFrame (GstBuffer *buffer, GstCaps *caps, float dt)
     if (active_)
     {
         // calculate dt in ns
-        timeframe_ +=  gst_gdouble_to_guint64( dt * 1000000.f);
+        timeframe_ +=  gst_gdouble_to_guint64( dt * 1000000.f );
 
         // if time is passed one frame duration (with 10% margin)
         // and if the encoder accepts data
diff --git a/ImGuiToolkit.cpp b/ImGuiToolkit.cpp
index dc701cf..286ed2c 100644
--- a/ImGuiToolkit.cpp
+++ b/ImGuiToolkit.cpp
@@ -124,7 +124,7 @@ void ImGuiToolkit::Icon(int i, int j)
     ImGui::Image((void*)(intptr_t)textureicons, ImVec2(ImGui::GetTextLineHeightWithSpacing(), ImGui::GetTextLineHeightWithSpacing()), uv0, uv1);
 }
 
-bool ImGuiToolkit::ButtonIcon(int i, int j)
+bool ImGuiToolkit::ButtonIcon(int i, int j, const char *tooltip)
 {
     // icons.dds is a 20 x 20 grid of icons 
     if (textureicons == 0)
@@ -137,6 +137,13 @@ bool ImGuiToolkit::ButtonIcon(int i, int j)
     bool ret =  ImGui::ImageButton((void*)(intptr_t)textureicons, ImVec2(ImGui::GetTextLineHeightWithSpacing(),ImGui::GetTextLineHeightWithSpacing()), uv0, uv1, 3);
     ImGui::PopID();
 
+    if (tooltip != nullptr && ImGui::IsItemHovered())
+    {
+        ImGui::BeginTooltip();
+        ImGui::Text("%s", tooltip);
+        ImGui::EndTooltip();
+    }
+
     return ret;
 }
 
diff --git a/ImGuiToolkit.h b/ImGuiToolkit.h
index 5e2a0eb..91dd1fd 100644
--- a/ImGuiToolkit.h
+++ b/ImGuiToolkit.h
@@ -15,7 +15,7 @@ namespace ImGuiToolkit
     void ShowIconsWindow(bool* p_open);
 
     // utility buttons
-    bool ButtonIcon (int i, int j);
+    bool ButtonIcon (int i, int j, const char* tooltip = nullptr);
     bool ButtonIconToggle (int i, int j, int i_toggle, int j_toggle, bool* toggle);
     bool ButtonIconMultistate (std::vector<std::pair<int, int> > icons, int* state);
     bool ButtonToggle(const char* label, bool* toggle);
diff --git a/Loopback.cpp b/Loopback.cpp
index bcca62c..612ed52 100644
--- a/Loopback.cpp
+++ b/Loopback.cpp
@@ -55,7 +55,7 @@ bool Loopback::system_loopback_initialized = false;
  * Useful command lines for debug
  * $ v4l2-ctl --all -d 10
  * $ gst-launch-1.0 v4l2src device=/dev/video10 ! videoconvert ! autovideosink
- * $ gst-launch-1.0 videotestsrc ! v4l2sink device=/dev/video1
+ * $ gst-launch-1.0 videotestsrc ! v4l2sink device=/dev/video10
  */
 
 #include <stdio.h>
@@ -64,7 +64,7 @@ bool Loopback::system_loopback_initialized = false;
 #include <unistd.h>
 
 std::string Loopback::system_loopback_name = "/dev/video10";
-std::string Loopback::system_loopback_pipeline = "appsrc name=src ! videoconvert ! v4l2sink sync=false name=sink";
+std::string Loopback::system_loopback_pipeline = "appsrc name=src ! videoconvert ! queue ! v4l2sink sync=false name=sink";
 
 bool Loopback::initializeSystemLoopback()
 {
@@ -87,6 +87,7 @@ bool Loopback::initializeSystemLoopback()
             // create command line for installing v4l2loopback
             std::string cmdline = "export SUDO_ASKPASS=\"" + sudoscript + "\"\n";
             cmdline += "sudo -A apt install v4l2loopback-dkms 2>&1\n";
+            cmdline += "sudo -A modprobe -r v4l2loopback 2>&1\n";
             cmdline += "sudo -A modprobe v4l2loopback exclusive_caps=1 video_nr=10 card_label=\"vimix loopback\" 2>&1\n";
 
             // execute v4l2 command line
diff --git a/UserInterfaceManager.cpp b/UserInterfaceManager.cpp
index 0bc12d3..a68709c 100644
--- a/UserInterfaceManager.cpp
+++ b/UserInterfaceManager.cpp
@@ -1314,22 +1314,26 @@ void UserInterface::RenderPreview()
 
         static char dummy_str[512];
         sprintf(dummy_str, "sudo apt install v4l2loopback-dkms");
-        ImGui::SetNextItemWidth(w + 20);
+        ImGui::Text("Install v4l2loopack:");
         ImGui::InputText("##cmd1", dummy_str, IM_ARRAYSIZE(dummy_str), ImGuiInputTextFlags_ReadOnly);
+        ImGui::SameLine();
+        ImGui::PushID(358794);
+        if ( ImGuiToolkit::ButtonIcon(3,6, "Copy to clipboard") )
+            ImGui::SetClipboardText(dummy_str);
+        ImGui::PopID();
+
         sprintf(dummy_str, "sudo modprobe v4l2loopback exclusive_caps=1 video_nr=10 card_label=\"vimix loopback\"");
-        ImGui::SetNextItemWidth(w + 20);
+        ImGui::Text("Initialize v4l2loopack:");
         ImGui::InputText("##cmd2", dummy_str, IM_ARRAYSIZE(dummy_str), ImGuiInputTextFlags_ReadOnly);
+        ImGui::SameLine();
+        ImGui::PushID(899872);
+        if ( ImGuiToolkit::ButtonIcon(3,6, "Copy to clipboard") )
+            ImGui::SetClipboardText(dummy_str);
+        ImGui::PopID();
 
         ImGui::Separator();
-        if (ImGui::Button("Cancel, I'll do it.\n(try again later)", ImVec2(w/2, 0))) { ImGui::CloseCurrentPopup(); }
-        ImGui::SameLine();
         ImGui::SetItemDefaultFocus();
-        if (ImGui::Button("Ok, let vimix try.\n(sudo password required)", ImVec2(w/2, 0)) ) {
-            if (Loopback::initializeSystemLoopback()) {
-                FrameGrabber *fg = new Loopback;
-                webcam_emulator_ = fg->id();
-                FrameGrabbing::manager().add(fg);
-            }
+        if (ImGui::Button("Ok, I'll do it and try again later.", ImVec2(w, 0)) ) {
             ImGui::CloseCurrentPopup();
         }