Creating a table with header row disabled breaks the content display.

[retUrn3d]

Version of Dear PyGui

Version: 2.0.0
Operating System: Windows 10

My Issue/Question

dpg.table() with header_row=False does not display adding new rows.

To Reproduce

1. Create dpg.table() with header_row=False
2. Try to add a row with any content.
3. nothing happens :(

Expected behavior

dpg.table() with header_row=False displays the addition of new rows.

Prior to version 2.0.0, everything worked as expected.

Screenshots/Video

Standalone, minimal, complete and verifiable example

import time
import dearpygui.dearpygui as dpg

dpg.create_context()

with dpg.window(tag='main_window'):
    with dpg.table(header_row=True, tag='test_table'):
        dpg.add_table_column(width_fixed=True)


def test():
    #  Don't judge me, I was too lazy to think.
    while True:
        dpg.render_dearpygui_frame()
        time.sleep(1)
        with dpg.table_row(parent='test_table'):
            dpg.add_text('TEST')



dpg.create_viewport(title='TEST')
dpg.set_primary_window('main_window', value=True)
dpg.setup_dearpygui()
dpg.show_viewport()
test()
dpg.start_dearpygui()
dpg.destroy_context()

[v-ein]

I've just bumped into this issue as well. It is caused by a fix in 2.0 for the show flag on table columns: they can now be shown and hidden via show/hide_item just like any other widget. Unfortunately it got a side effect (in Dear ImGui) of hiding the column at render stage if it doesn't contain any contents to render. I'm going to fix that.

[v-ein]

Technically, it's a problem in Dear ImGui, but it will be much easier and faster to fix it on DPG side. It is caused by ImGui::TableGetColumnFlags() incorrectly returning zero bits in some flags. This occurs if the table is empty on the very first frame it is rendered. The flags are internally set up by ImGui::TableUpdateLayout(), which is typically called at the start of the first row. However, an empty table does not have "the first row", which means TableUpdateLayout() only occurs in ImGui::EndTable() -- and it's too late to call TableGetColumnFlags() after that.

My assumption is that ImGui::TableGetColumnFlags() should probably invoke ImGui::TableUpdateLayout() on its own.

To fix it in DPG, I've added a check that skips flags update for the show flag if the table is empty. I'll push the fix later, when I'm done with upgrading to DPG 2.0.