I think it's a very old bug in the tables. about imgui

[PathogenDavid]

In the legacy columns API (which is separate from the modern tables API), Columns(1); means "no columns", hence the failed assert. You can see this demonstrated in the demo:

imgui/imgui_demo.cpp

Lines 3521 to 3528 in 9504068

	ImGui::Text("Columns:");
	ImGui::Columns(4);
	for (int n = 0; n < 4; n++)
	{
	ImGui::Text("Width %.2f", ImGui::GetColumnWidth());
	ImGui::NextColumn();
	}
	ImGui::Columns(1);

In cases where you want a single column, you can use the internal BeginColumns function:

ImGui::BeginColumns("tabs", 1, ImGuiOldColumnFlags_NoBorder);
ImGui::SetColumnWidth(0, 100.f);
ImGui::TextWrapped("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed sit amet nisl fringilla, pulvinar nibh nec, elementum tellus.");
ImGui::EndColumns();

Ideally though you should just migrate to the new tables API (and update to a newer version of Dear ImGui, 1.76 is pretty old.)