Fix preview with a nested preview not being shown (#10795)

Regression at db581113.

(cherry picked from commit 94c65074e029937b549f5ed5af1001fadbe408be)

diff --git a/src/graphics/PreviewLoader.cpp b/src/graphics/PreviewLoader.cpp
index 22b0f23ead20d78025e22ef09130f0491bc68c83..ac14fbb6a904591e9b8a0182bef5b230eb7ae3e6 100644 (file)
--- a/src/graphics/PreviewLoader.cpp
+++ b/src/graphics/PreviewLoader.cpp
@@ -239,7 +239,7 @@ private:
        /// We don't own this
        static lyx::Converter const * pconverter_;
 
-       signals2::scoped_connection connection_;
+       Trackable trackable_;
 };
 
 
@@ -738,10 +738,9 @@ void PreviewLoader::Impl::startLoading(bool wait)
 
        // Initiate the conversion from LaTeX to bitmap images files.
        ForkedCall::sigPtr convert_ptr = make_shared<ForkedCall::sig>();
-       // This is a scoped connection
-       connection_ = convert_ptr->connect([this](pid_t pid, int retval){
-                       finishedGenerating(pid, retval);
-               });
+       convert_ptr->connect(ForkedProcess::slot([this](pid_t pid, int retval){
+                               finishedGenerating(pid, retval);
+                       }).track_foreign(trackable_.p()));
 
        ForkedCall call(buffer_.filePath());
        int ret = call.startScript(command, convert_ptr);