Can't select Combo with keyboard

[slajerek]

Version/Branch of Dear ImGui:

Version: 1.82 (2021/XX/XX (1.XX) - when multi-viewports are enabled....)
Branch: docking

Back-end/Renderer/Compiler/OS

Back-ends: imgui_impl_opengl3.cpp + imgui_impl_sdl.cpp
Operating System: macOS/Windows/Linux

My Issue/Question:

I can not make Combo accessible using keyboard. I can easily move between InputInt items using TAB keyboard and enter data there using keyboard, but TAB does not stop on Combo, also I can not select items from Combo by keyboard.

I tried ImGuiConfigFlags_NavEnableKeyboard flag, however that is not correct way as this navigates using arrow keys and a spacebar, which is not default behaviour in modern OS (i.e. move focus should be achieved using TAB).

It seems Tab stop is not working for Combo.

Screenshots/Video

Standalone, minimal, complete and verifiable example:

// Here's some code anyone can copy and paste to reproduce the issue
ImGui::Begin("Example Bug");

	static int frame = 0;
	if (frame < 2)
	{
		ImGui::SetKeyboardFocusHere();
		frame++;
	}
	
	const char *items[] = { "Item 1", "Item 2", "Item 3" };
	static int selectedItemNum = 0;
	if (ImGui::BeginCombo("combo", items[selectedItemNum]))
	{
		for (int n = 0; n < IM_ARRAYSIZE(items); n++)
		{
			bool isSelected = (selectedItemNum == n);
			if (ImGui::Selectable(items[n], isSelected))
			{
				selectedItemNum = n;
			}
			if (isSelected)
				ImGui::SetItemDefaultFocus();
		}
		ImGui::EndCombo();
	}
	
	static int val1 = 0;
	ImGui::InputInt("input 1", &val1);

	static int val2 = 0;
	ImGui::InputInt("input 2", &val2);

	static int val3 = 0;
	ImGui::InputInt("input 3", &val3);

ImGui::End();

[ocornut]

The nav system currently doesn't support that.
It is planned we will someday but it's not currently the case.
I've done some work on it for #4079 and a private branch but we are currently stuck finishing it due to a scrolling issue. I think tabbing should be reengineered to use same deferred logic as directional navigation.

I'll close this as duplicate of existing issues incl #3092 #3208