disabledTrue disables interaction and dims following items until EndDisabled(); nested disabled scopes remain disabled.
Disable all user interactions and dim items visuals (applying style.DisabledAlpha over current colors)
Those can be nested but it cannot be used to enable an already disabled section (a single BeginDisabled(true) in the stack is enough to keep everything disabled)
Tooltips windows by exception are opted out of disabling.
BeginDisabled(false)/EndDisabled() essentially does nothing but is provided to facilitate use of boolean expressions (as a micro-optimization: if you have tens of thousands of BeginDisabled(false)/EndDisabled() pairs, you might want to reformulate your code to avoid making those calls)
Begin a scope that can disable user interaction.