Tables: Clarified that TableSetColumnEnabled() requires the table to use the ImGuiTableFlags_Hideable flag. (#3935)

docs/CHANGELOG.txt

@@ -37,6 +37,8 @@ HOW TO UPDATE?
 
 Other Changes:
 - TabBar: Fixed using more than 32 KB-worth of tab names. (#4176)
+- Tables: Clarified that TableSetColumnEnabled() requires the table to use the ImGuiTableFlags_Hideable flag,
+  because it manipulates the user-accessible show/hide state. (#3935)
 - Tables: Added ImGuiTableColumnFlags_NoHeaderLabel to request TableHeadersRow() to not submit label for a column.
   Convenient for some small columns. Name will still appear in context menu. (#4206).
 - Tables: Fix columns order on TableSetupScrollFreeze() if previous data got frozen columns out of their section.

imgui_tables.cpp

@@ -1499,7 +1499,7 @@ void ImGui::TableSetupScrollFreeze(int columns, int rows)
 // - TableGetColumnCount()
 // - TableGetColumnName()
 // - TableGetColumnName() [Internal]
-// - TableSetColumnEnabled() [Internal]
+// - TableSetColumnEnabled()
 // - TableGetColumnFlags()
 // - TableGetCellBgRect() [Internal]
 // - TableGetColumnResizeID() [Internal]
@@ -1535,10 +1535,11 @@ const char* ImGui::TableGetColumnName(const ImGuiTable* table, int column_n)
     return &table->ColumnsNames.Buf[column->NameOffset];
 }
 
-// Request enabling/disabling a column (often perceived as "showing/hiding" from users point of view)
+// Change user accessible enabled/disabled state of a column (often perceived as "showing/hiding" from users point of view)
 // Note that end-user can use the context menu to change this themselves (right-click in headers, or right-click in columns body with ImGuiTableFlags_ContextMenuInBody)
-// Request will be applied during next layout, which happens on the first call to TableNextRow() after BeginTable()
+// - Require table to have the ImGuiTableFlags_Hideable flag because we are manipulating user accessible state.
-// For the getter you can use (TableGetColumnFlags() & ImGuiTableColumnFlags_IsEnabled)
+// - Request will be applied during next layout, which happens on the first call to TableNextRow() after BeginTable().
+// - For the getter you can test (TableGetColumnFlags() & ImGuiTableColumnFlags_IsEnabled) != 0.
 void ImGui::TableSetColumnEnabled(int column_n, bool enabled)
 {
     ImGuiContext& g = *GImGui;
@@ -1546,6 +1547,7 @@ void ImGui::TableSetColumnEnabled(int column_n, bool enabled)
     IM_ASSERT(table != NULL);
     if (!table)
         return;
+    IM_ASSERT(table->Flags & ImGuiTableFlags_Hideable); // See comments above
     if (column_n < 0)
         column_n = table->CurrentColumn;
     IM_ASSERT(column_n >= 0 && column_n < table->ColumnsCount);