Minor fix to avoid undefined behavior sanitizer triggering (#3276)

imgui.cpp

@@ -3516,7 +3516,7 @@ static void ImGui::UpdateMouseInputs()
                 ImVec2 delta_from_click_pos = IsMousePosValid(&g.IO.MousePos) ? (g.IO.MousePos - g.IO.MouseClickedPos[i]) : ImVec2(0.0f, 0.0f);
                 if (ImLengthSqr(delta_from_click_pos) < g.IO.MouseDoubleClickMaxDist * g.IO.MouseDoubleClickMaxDist)
                     g.IO.MouseDoubleClicked[i] = true;
-                g.IO.MouseClickedTime[i] = -DBL_MAX;    // so the third click isn't turned into a double-click
+                g.IO.MouseClickedTime[i] = -g.IO.MouseDoubleClickTime * 2.0f; // Mark as "old enough" so the third click isn't turned into a double-click
             }
             else
             {