Dropdown issues

[aliabid94]

This PR fixes a lot of the dropdown issues raised by @space-nuko. GIF below shows new behavior of dropdown:

code for demo at bottom.

Changes in this PR:

• Changes cursor from select to pointer in single dropdown mode
• Allows dropdown to be re-clicked after focus (fixes: gr.Dropdown doesn't close when clicked on twice #3532)
• Prevents dropdown from getting clipped by calculating size from ends of window, and directing dropdown toward side with more space. Will use full window space, and scroll beyond that (fixes: gr.Dropdown items can get cut off at the bottom of the page #3539, fixes: gr.Dropdown's default size is much too small #3530).
• Overflow only happens in y-direction, no horizontal scrollbars (fixes: gr.Dropdown can cause X overflow/ugly scrollbars #3533)
• Search when multiselect=False (fixes: Can't type a prefix to search through gr.Dropdown items when multiselect is off #3538)

import gradio as gr

with gr.Blocks() as demo:
    gr.Markdown(
    """
    # Hello World!
    Start typing below to see the output.
    """)
    gr.Dropdown(list("abcd"))
    gr.Dropdown(list("abcdefghijklmnopqrstuvwxyz"))
    gr.Dropdown(list("abcdefghijklmnopqrstuvwxyz"), multiselect=True)
    gr.Dropdown(list("abcd"))
    gr.HTML("""
    <div style="height: 600px; width: 240px; background-color: blue"></div>
    """)

if __name__ == "__main__":
    demo.launch()

[gradio-pr-bot]

All the demos for this PR have been deployed at https://huggingface.co/spaces/gradio-pr-deploys/pr-3549-all-demos

[abidlabs]

Tested and works well @aliabid94. Nice PR!

[space-nuko]

LGTM 👍

[space-nuko]

Actually there's one issue I found, it has to do with the multiselect dropdown

Every other time you click on a choice it closes the list, even though you could still select/unselect other options

output.webm

[gradio-pr-bot]

The demo notebooks don't match the run.py files. Please run this command from the root of the repo and then commit the changes:

pip install nbformat && cd demo && python generate_notebooks.py

[aliabid94]

Fixed the issue space nuko pointed out. Also moved the dropdown so it does not cover the input text. Also now you can type to search when multiselect=False, fixes #3538

[abidlabs]

Nice fixes @aliabid94! Thanks for raising these great issues @space-nuko