First, I love Delphi (20 years use) and FireMonkey (5 years use – Android). My thoughts are criticisms, not a rejection.
Leave it to FireMonkey for making an experienced Delphi developer’s day frustrating.
When you change tabs on a TTabControl, chances are you want to place focus on a component on the current tab. Well, there is no “OnChanged event” to accomplish this. Luckily I found this code on a Russian website*.
procedure DelayedSetFocus(control: TControl);
What this code does is delays setting focus on the “control” until the TTabControl tab changes to the new tab.
For example, you have a TTabControl with two (2) TTabItems named tiInfo and tiSysSet. You add code to the tab item you want to set focus on a control.
Code the following to the tab item click event:
procedure TfrmHelp.tiSysSetClick(Sender: TObject);
If coding for an iOS/Android, do not forget to add the tab item tap event.
procedure TfrmHelp.tiSysSetTap(Sender: TObject);
Simple and it works.