GUI: even more piano work

- don't allow piano window to be moved if clicking on piano
- only treat left click as a touch point

src/gui/gui.cpp

@@ -2314,6 +2314,7 @@ void FurnaceGUI::processPoint(SDL_Event& ev) {
       break;
     }
     case SDL_MOUSEBUTTONDOWN: {
+      if (ev.button.button!=SDL_BUTTON_LEFT) break;
       for (size_t i=0; i<activePoints.size(); i++) {
         TouchPoint& point=activePoints[i];
         if (point.id==-1) {
@@ -2332,6 +2333,7 @@ void FurnaceGUI::processPoint(SDL_Event& ev) {
       break;
     }
     case SDL_MOUSEBUTTONUP: {
+      if (ev.button.button!=SDL_BUTTON_LEFT) break;
       for (size_t i=0; i<activePoints.size(); i++) {
         TouchPoint& point=activePoints[i];
         if (point.id==-1) {

src/gui/piano.cpp

@@ -209,6 +209,7 @@ void FurnaceGUI::drawPiano() {
       // render piano
       //ImGui::ItemSize(size,ImGui::GetStyle().FramePadding.y);
       if (ImGui::ItemAdd(rect,ImGui::GetID("pianoDisplay"))) {
+        ImGui::ItemHoverable(rect,ImGui::GetID("pianoDisplay"));
         if (view) {
           int notes=oct*12;
           // evaluate input