SplitterBehavior: tweak to not assert due to floating point precision.

Not guaranting behavior: clamping makes output lossy, size_1+size_2 in theory may be instable but couldn't repro.
API probably needs rework anyhow (should redistribute from provided available space).

imgui_widgets.cpp

@@ -1564,8 +1564,7 @@ bool ImGui::SplitterBehavior(const ImRect& bb, ImGuiID id, ImGuiAxis axis, float
     ImRect bb_render = bb;
     if (held)
     {
-        ImVec2 mouse_delta_2d = g.IO.MousePos - g.ActiveIdClickOffset - bb_interact.Min;
-        float mouse_delta = (axis == ImGuiAxis_Y) ? mouse_delta_2d.y : mouse_delta_2d.x;
+        float mouse_delta = (g.IO.MousePos - g.ActiveIdClickOffset - bb_interact.Min)[axis];
 
         // Minimum pane size
         float size_1_maximum_delta = ImMax(0.0f, *size1 - min_size1);
@@ -1578,12 +1577,8 @@ bool ImGui::SplitterBehavior(const ImRect& bb, ImGuiID id, ImGuiAxis axis, float
         // Apply resize
         if (mouse_delta != 0.0f)
         {
-            if (mouse_delta < 0.0f)
-                IM_ASSERT(*size1 + mouse_delta >= min_size1);
-            if (mouse_delta > 0.0f)
-                IM_ASSERT(*size2 - mouse_delta >= min_size2);
-            *size1 += mouse_delta;
-            *size2 -= mouse_delta;
+            *size1 = ImMax(*size1 + mouse_delta, min_size1);
+            *size2 = ImMax(*size2 - mouse_delta, min_size2);
             bb_render.Translate((axis == ImGuiAxis_X) ? ImVec2(mouse_delta, 0.0f) : ImVec2(0.0f, mouse_delta));
             MarkItemEdited(id);
         }