ImGui::BeginPopup being cropped at first open

[eduardodoria]

Version/Branch of Dear ImGui:

Version 1.91.5, Branch: docking

Back-ends:

imgui_impl_glfw.cpp + imgui_impl_opengl3.cpp

Compiler, OS:

Linux + GCC

Full config/build information:

No response

Details:

When I open a popup with a table inside, at first time it has been cropped but next times its is ok.

I can fix this behavior adding ImGui::SetNextWindowSizeConstraints(ImVec2(400, 0), ImVec2(FLT_MAX, FLT_MAX)); before ImGui::BeginPopup but it is not good because the size of the table inside popup will vary.

I think popup not know its size before first open. Is this the correct behavior or a bug?

Screenshots/Video:

Gravacao.de.tela.de.2024-12-01.11-51-14.webm

Minimal, Complete and Verifiable Example code:

if (ImGui::Button(ICON_FA_GEAR)){
    ImGui::OpenPopup(("menusettings_"+prop.name).c_str());
}
//ImGui::SetNextWindowSizeConstraints(ImVec2(400, 0), ImVec2(FLT_MAX, FLT_MAX));
if (ImGui::BeginPopup(("menusettings_"+prop.name).c_str())){
    ImGui::Text("%s settings", prop.label.c_str());
    ImGui::Separator();

    drawPropertiesTable(cpType, prop.childs, scene, entity, "_child_"+prop.name, 200);

    ImGui::EndPopup();
}

[ocornut]

We are missing too many details to provide guidance.

• Why in the second open the popup is moved to the left? Is the dark window an actual platform/os window? What's the left and right of it?

• Can you confirm if the window is mis-sized or if it is cropped? IMGUI_DEBUG_LOG("%f %f\n", ImGui::GetWindowSize().x, ImGui::GetWindowSize().y); would work. You can see additional details in Metrics/Debugger.

[eduardodoria]

Why in the second open the popup is moved to the left? Is the dark window an actual platform/os window? What's the left and right of it?

A better video here opening tree times:
Gravação de tela de 2024-12-03 14-12-42.webm

Can you confirm if the window is mis-sized or if it is cropped? IMGUI_DEBUG_LOG("%f %f\n", ImGui::GetWindowSize().x, ImGui::GetWindowSize().y); would work. You can see additional details in Metrics/Debugger.

(first open)
16.000000 16.000000
122.000000 144.000000
289.000000 144.000000
289.000000 144.000000
289.000000 144.000000
[...]
(second open)
16.000000 16.000000
289.000000 144.000000
289.000000 144.000000
289.000000 144.000000
[...]
(third open)
16.000000 16.000000
289.000000 144.000000
289.000000 144.000000
[...]