SetKeyboardFocusHere() added assert to prevent passing values smaller than -1 as we may have to outlaw them (I think nobody was using that)

imgui.cpp

@@ -5457,6 +5457,7 @@ void ImGui::SetScrollHere(float center_y_ratio)
 
 void ImGui::SetKeyboardFocusHere(int offset)
 {
+    IM_ASSERT(offset >= -1);    // -1 is allowed but not below
     ImGuiWindow* window = GetCurrentWindow();
     window->FocusIdxAllRequestNext = window->FocusIdxAllCounter + 1 + offset;
     window->FocusIdxTabRequestNext = INT_MAX;

imgui.h

@@ -176,7 +176,7 @@ namespace ImGui
     IMGUI_API void          SetScrollY(float scroll_y);                                         // set scrolling amount [0..GetScrollMaxY()]
     IMGUI_API void          SetScrollHere(float center_y_ratio = 0.5f);                         // adjust scrolling amount to make current cursor position visible. center_y_ratio=0.0: top, 0.5: center, 1.0: bottom.
     IMGUI_API void          SetScrollFromPosY(float pos_y, float center_y_ratio = 0.5f);        // adjust scrolling amount to make given position valid. use GetCursorPos() or GetCursorStartPos()+offset to get valid positions.
-    IMGUI_API void          SetKeyboardFocusHere(int offset = 0);                               // focus keyboard on the next widget. Use positive 'offset' to access sub components of a multiple component widget. Use negative 'offset' to access previous widgets.
+    IMGUI_API void          SetKeyboardFocusHere(int offset = 0);                               // focus keyboard on the next widget. Use positive 'offset' to access sub components of a multiple component widget. Use -1 to access previous widget.
     IMGUI_API void          SetStateStorage(ImGuiStorage* tree);                                // replace tree state storage with our own (if you want to manipulate it yourself, typically clear subsection of it)
     IMGUI_API ImGuiStorage* GetStateStorage();