Suggestion: add possibility to affect popup fallback position policy

[IceLuna]

Version/Branch of Dear ImGui:

Version 1.92.4, Branch: docking

Back-ends:

imgui.cpp

Compiler, OS:

Win10, MSVC 2022

Full config/build information:

No response

Details:

Hi! I'm using imgui-node-editor and BeginCombo is rendered in the wrong position within the editor (see the first screenshot). And I found out that it's because fallback login inside in the end of FindBestWindowPosForPopupEx() (see the second screenshot). It tries to keep the position within bounds, but in the editor, coords can go out of the bounds. If I remove these two lines, it works as expected.

Is it possible to add an API to disable this fallback logic and make it return ref_pos without the clamp? I can implement it in my ImGui fork, but it'd be nice if it was official, hence the question if you think it's reasonable. I could probably prepare a PR myself, but I'm not sure how the API should look like.

Maybe something like?

ImGui::SetPopupSizeClampingEnabled(false); // Temporarily disable clamp within the editor
ImGui::BeginCombo();
ImGui::SetPopupSizeClampingEnabled(true); // Enable back

Screenshots/Video:

BeginCombo being rendered in the wrong position

Minimal, Complete and Verifiable Example code:

[ocornut]

This seems like a XY Problem.

The problem to solve and question to ask is why that combo is incorrectly positioned in the first place.

I believe imgui-node-editor does a reprojection of emitted vertices and the popup position is locked before the reprojection.
This is probably something to ask in the imgui-node-editor project. cc @thedmd I'm open to exploring/implementing solutions on my end if required, but arbitrary disabling this behavior doesn't seem like the correct solution.