Redundant scrollbar with BeginChild inside a table

[nem0]

Version/Branch of Dear ImGui:

Version: 07d1709 (the latest)
Branch: docking

Back-end/Renderer/Compiler/OS

Back-ends: imgui_impl_dx9.cpp + imgui_impl_win32.cpp, but also custom backend
Compiler: VS2022
Operating System: Win10

My Issue/Question:

I'm trying to use table API instead of old columns API to create layout like in the attached screenshot, but there is unnecessary scrollbar, caused by child window inside table. It works fine when using columns API.

Screenshots/Video

Standalone, minimal, complete and verifiable example:

    if (ImGui::Begin("test3")) {
        if (ImGui::BeginTable("tab", 2, ImGuiTableFlags_Resizable))    {
            ImGui::TableNextRow();
            ImGui::TableNextColumn();
            ImGui::BeginChild("foo");
            ImGui::EndChild();
            ImGui::TableNextColumn();
            ImGui::EndTable();
        }
    }
    ImGui::End();

[ocornut]

Hello,
Thanks for the report.
I am working on the correct answer for this. The full picture is a little complicated.
In the meanwhile, the temporary workaround would be to reduce child height:

ImGui::BeginChild("foo", ImVec2(0.0f, -ImGui::GetStyle().CellPadding.y));

(It's only temporary as once fixed you would not need it as it would add unnecessary padding)

[ocornut]

I pushed a fix for a tangential issue 2bc5d17 (+ test ocornut/imgui_test_engine@03da9cd) I need to fix before yours, but this is not the fix you need yet.

[ocornut]

I pushed a fix db66e33. If you cherry-pick both 2bc5d17 and db66e33 it'll merge in docking branch.
EDIT Merged into docking too now.

Not done with the tests, but for reference here's my test bed

if (ImGui::Begin("Test #6619"))
{
    static ImGuiTableFlags table_flags = ImGuiTableFlags_Resizable | ImGuiTableFlags_Borders;
    static ImVec2 table_size = ImVec2(0.0f, 0.0f);
    ImVec2 sz1 = ImGui::GetContentRegionAvail();
    ImVec2 sz2;
    ImGui::ColorButton("##blah1", { 1,1,0,0.5f }, 0, { 50,300 });
    ImGui::SameLine();
    if (ImGui::BeginTable("Table", 2, table_flags, table_size))
    {
        ImGui::TableNextRow();
        ImGui::TableNextColumn();
        sz2 = ImGui::GetContentRegionAvail();
        if (0)
        {
            ImGui::Button("Fill", ImVec2(-FLT_MIN, -FLT_MIN));
        }
        else
        {
            ImGui::PushStyleColor(ImGuiCol_ChildBg, { 0,1,0,0.5f });
            ImGui::BeginChild("foo");// , ImVec2(0.0f, -ImGui::GetStyle().CellPadding.y * 2.0f));
            ImVec2 child_size = ImGui::GetWindowSize();
            ImGui::Text("\n\n\nChild %.2f, %.2f", child_size.x, child_size.y);
            ImGui::EndChild();
            ImGui::PopStyleColor();
        }
        ImGui::TableNextColumn();
        ImGui::ColorButton("##blah1", { 1,0,1,0.5f }, 0, { 50,250 });
        ImGui::EndTable();
    }
    ImGui::Begin("test4");
    ImGui::Text("Avail %f %f", sz1.x, sz1.y);
    ImGui::Text("Avail %f %f", sz2.x, sz2.y);
    ImGui::CheckboxFlags("NoHostExtendY", &table_flags, ImGuiTableFlags_NoHostExtendY);
    ImGui::CheckboxFlags("ScrollY", &table_flags, ImGuiTableFlags_ScrollY);
    ImGui::InputFloat2("TableSize", &table_size.x);
    ImGui::End();
}
ImGui::End();

[ocornut]

Closing this as solved.

[nem0]

Thank you, it does fix my issue.