How do I find my way around the code?

I’ve been tasked with adding something to the UI of QGC. I started by running it in Callgrind and twiddling a button, but the time spent responding to the button was so tiny I couldn’t find it. Then I ran gdb on it and stopped it and tried to single-step into an event handler, but not having the source code of whatever I stopped it in, I couldn’t. Then I grepped the files in ~/src/qgroundcontrol/src/ for QButton, QMenu, QLabel, and QComboBox. The only one of those I found is QComboBox, which is subclassed to QGCComboBox, which isn’t used anywhere. Where can I start understanding the UI code?

Ui src is mostly done on the .qml files. QButton etc are an extension to qml Button, mainly for auto change colors to the chosen dark or light color theme.
FlightView.qml and FlightMap.qml are good starting points to study the code.
Further read qt qml language and qt signaling techniques.

Thanks! I’m not familiar with qml; in my code I put the classes defining UI in header files, such as tincanvas.h, with the implementation in source files, such as tincanvas.cpp. Signals are connected by methods of the classes. I don’t see any .cpp (or .cc) files in qgroundcontrol/src/ui/toolbar/; where’s a method I can set a breakpoint on?

Here is how I go about it:
I find a distinct phrase around the control I want to edit, ctrl+shift+f it and generally find it on qml, after that I continue to ctrl+shift+f my way back to a Q_property or Q_invokable, fallowing binded signals and variables. after that you could put a break point in there.
I am not very experienced with qt, so this might not be optimal

ctrl-shift-f makes Kate go full-screen. What editor are you using, and what does ctrl-shift-f do?