We have at least two possible ways to fix the warnig:
* Disallow move constructors and assignment operators for all GUI elements
* Allow move constructor and assignment operator for `IGUISetting`
I've tried the second one.
Warning:
```
In file included from ../../../source/pch/gui/precompiled.h:27:
In file included from ../../../source/gui/ObjectBases/IGUIObject.h:29:
../../../source/gui/SettingTypes/CGUIHotkey.h:37:2: warning: explicitly defaulted move assignment operator is implicitly deleted [-Wdefaulted-function-deleted]
MOVABLE(CGUIHotkey);
^
../../../source/lib/code_annotation.h:237:13: note: expanded from macro 'MOVABLE'
className& operator=(className&&) = default
^
../../../source/gui/SettingTypes/CGUIHotkey.h:31:20: note: move assignment operator of 'CGUIHotkey' is implicitly deleted because base class 'CGUISimpleSetting<CStr8>' has a deleted move assignment operator
class CGUIHotkey : public CGUISimpleSetting<CStr>
^
../../../source/gui/CGUISetting.h:91:2: note: 'operator=' has been explicitly marked deleted here
NONCOPYABLE(CGUISimpleSetting);
^
../../../source/lib/code_annotation.h:229:13: note: expanded from macro 'NONCOPYABLE'
className& operator=(const className&) = delete
```