From Free Pascal wiki
Jump to navigationJump to search

English (en) русский (ru)

The DockedFormEditor is a package for the Lazarus IDE that docks a form next to source editor unit. This package is shipped with Lazarus version 2.1 upwards.

Why is it useful?

If you don't like to search a form related to a unit, you can switch in the source editor pages. There you find the form docked as tab. Useful is a combination of packages AnchorDockingDsgn with DockedFormEditor, if you don't like the default "separate windows" look of the Lazarus IDE and prefer a single window.

DockedFormEditor is the replacement and initially forked form Sparta_DockedFormEditor. If you used this package in the past, please switch to DockedFormEditor as all Sparta packages are now defined as deprecated and will be removed in a future version of Lazarus.


  • Uninstall any other docking managers (e.g., easydockmgrdsgn) and especially Sparta_DockedFormEditor!
  • Install this package (and maybe AnchorDockingDsgn) per MainMenu -> Package -> Install/Uninstall Packages... -> check the package dockedformeditor.
  • Now recompile Lazarus IDE.


After installation there are the design tabs docked next to source editor unit:




In the tab Code is the source editor, where you can implement the logic of your app.



In the tab Form is the default form designer. Without this package it is a separate window.



In the tab Anchors is a optional anchor designer. It's follows the WYSIWYG concept and your form reacts at runtime the same as at designtime. It can be used simultaneously with default Anchor Editor:

  • You can snap a control border or point with the grips and anchor it to a next or parent control.
  • Sizing or positioning without anchoring are possible with mouse.
  • With <Ctrl> + mouse you can change the border around a control.
  • Constraints of a control are noted.
  • Per popup menu a control can simply fixed on paranet or this fixing can be removed.
  • All properties affected per Anchor Designer are shown in hint of control.



There are some options, found after package installation, under MainMenu -> Tools -> Options ... -> Docked Form Editor. Next to some color definitions you find:

  • Tab position: defines the position of the tabs Code, Form, Anchors
  • Force Refreshing At Sizing: if the resizing eats to much time, this option can be deactivated
  • Capture Distance: this is the minimal distance in pixel to catch a control with mouse
  • Automatically treat Align properties: the Anchor Designer can only work with Anchors, so Aligns are translated to Anchors when this option is activated
  • Automatically treat BorderSpacing properties: allow Anchor designer to change all Borders (Around, Left, Top, Right, Bottom) to fit in
  • Allow size changing: you can change the size of a control or you can really only set or remove Anchors and BorderSpacing


  • Tested on Windows7, 10, Linux Mint Cinnamon with GTK2, QT4, QT5.

Known Issues

  • When the designed form / frame is moved out of screen, there the form has no designer grid (dots).
  • Qt5 shows own menu in form, this isn't shown in the anchor designer.
  • Designer: mouse wheel to scroll content doesn't work - csDesigning is set and form doesn't get a LM_MOUSEWHEEL message.
  • If main menu is visible, the height of the client area is wrong, see Issue #38701
  • Form size is limited to screen size
  • AnchorDesigner: Child controls of some controls like TPageControl aren't visible

See also