When trying to load a previously saved title in a new title, Kdenlive crashes. It suffices to save a simple title with just a text, and then reloading it in a new title.

Before the segfault I see this:

Invalid URL: QUrl("/home/xxxxx/Videos/kdenlive/titles")
Thread 1 "kdenlive" received signal SIGSEGV, Segmentation fault.
0x00007ffff395bef3 in QGraphicsItem::sceneBoundingRect() const () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5

Running Kdenlive under gdb gives this backtrace (only the first few lines given):
#0  0x00007ffff395bef3 in QGraphicsItem::sceneBoundingRect() const () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
No symbol table info available.
#1  0x0000000000839c1d in TitleWidget::displayBackgroundFrame() ()
No symbol table info available.
#2  0x0000000000841ce9 in TitleWidget::adjustFrameSize() ()
No symbol table info available.
#3  0x00000000008408d1 in TitleWidget::setXml(QDomDocument const&) ()
No symbol table info available.
#4  0x000000000083fd62 in TitleWidget::loadTitle(QUrl) ()
No symbol table info available.
#5  0x000000000097cba9 in TitleWidget::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
No symbol table info available.
#6  0x00007ffff20e3fca in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.


Reproducible: Always

Steps to Reproduce:
1. Start a new Kdenlive project.
2. Add a new title clip.
3. In the title editor: add some text.
4. In the title editor: save title
5. Close title editor.
6. Add another new title clip.
7. In the title editor: load the previously saved title.

Actual Results:  
Kdenlive crashes with a segmentation fault.

Expected Results:  
Previously saved title is correctly reloaded without crashing.