Function Validate

src/command/edit.cpp:889–896

	CMD_TYPE(COMMAND_VALIDATE)

	bool Validate(const agi::Context *c) override {
		bool can_paste = !c->selectionController->GetSelectedSet().empty();
		if (can_paste && wxTheClipboard->Open()) {
			can_paste = wxTheClipboard->IsSupported(wxDF_TEXT) || wxTheClipboard->IsSupported(wxDF_UNICODETEXT);
			wxTheClipboard->Close();
		}
		return can_paste;
	}

	void operator()(agi::Context *c) override {
		auto const& sel = c->selectionController->GetSelectedSet();