Add docs about new functional

README.md

@@ -3,19 +3,22 @@ A handcrafted 1-1 Java binding for [Dear-ImGui](https://github.com/ocornut/imgui
 
 *Some of the very specific features are still in a wip state.*
 
-### How to use
+## How to use
 TBA
 
-##### Specifics of usage
-* Since it's a 1-1 binding please consider to see official [documentation](https://github.com/ocornut/imgui#usage) and [wiki](https://github.com/ocornut/imgui/wiki) to get more info about how to do things.
+##### Binding notice:
+* Since it's a 1-1 binding please consider to see official [documentation](https://github.com/ocornut/imgui#usage) and [wiki](https://github.com/ocornut/imgui/wiki) 
+  to get more info about how to do things.
 * In places where in C++ you need to pass `ImVec2` or `ImVec4`, you'll need to pass two or four float parameters respectively.
 * When you need to get an output from the Dear-ImGui use wrappers for primitives: `ImBool`, `ImInt` etc.
+* Due to the Java and JNI restrictions we can't provide a fully fledged callbacks to the ImGui::InputText*() methods.
+  Partly you could replace some of the features (like providing of the allowed chars to input) by using the ImGuiInputTextData class. Read javadoc to get more info.
 
-### How to build
+## How to build
 TBA
 
-### Credits
+## Credits
 This binding is based on the work of [xpenatan](https://github.com/xpenatan) and his version of the binding [jDear-imgui](https://github.com/xpenatan/jDear-imgui).
 
-### License
+## License
 See the LICENSE file for license rights and limitations (Apache-2.0).