Imgui: Crash in the Console example when I resize the window to minimal possible height

[geneotech]

sdl_opengl3_example: ../../imgui.cpp:4551: bool ImGui::Begin(const char*, bool*, ImGuiWindowFlags): Assertion `window_size_x_set_by_api && window_size_y_set_by_api' failed.

Repro:

• Pulled the repo at https://github.com/ocornut/imgui/commit/b016215c80f64fef17b8aaad843167c3c8d3855b
• built sdl_opengl3_example with make
• run ./sdl_opengl3_example from the folder
• Examples->Console
• Immediately resize the window to decrease the height as much as is possible

[ocornut]

@geneotech Should be fixed now. The bug didn't have much side effects because this is the point where the windows are all too small and/or clipped, but adding asserts recently made it more visible.

[geneotech]

Much appreciated! Keep up the excellent work!