Panning in Vcl Controls

[pyscripter 694]

You probably have noticed that when you press the middle mouse button in the Delphi IDE the editor goes into panning mode, that allows you to scroll by moving the mouse.   Many of the Vcl.Controls are panning enabled including the Memos, Grids, ContolLists, TabControls, Treeviews and others.   For a complete list just search for csPannable in the Delphi Vcl source code folder.   They use the exact same code that the IDE uses and behave in exactly the same way.  However, what you may not know (I did not), is that to enable panning you need to include in your project the Vcl.IMouse unit.  Vcl also makes it easy to add panning to your custom controls.  All it takes is to add the csPannable control style.  So SynEdit now has the same panning support as the Delphi IDE.

 

However, I have discovered two bugs related to Vcl panning:

• Memory leak when you use Vcl.IMouse - RAD Studio Service - Jira Service Management
• The Panning Window is not DPI scaled - RAD Studio Service - Jira Service Management

 

Both are easy to fix, so hopefully Embarcadero will provide fixes soon enough!  In the meantime, it is easy to work around the memory leak and hopefully live with the second one, which also affects the Delphi IDE.

Edited December 6 by pyscripter