[update] complete inbuilt extra elements guide, minor corrections in api

Author: mafanya23

data/api/gantt_adjusttaskheightforbaselines.md

@@ -21,4 +21,6 @@ Typically, there is no need to call this method directly. It is necessary only w
 api/gantt_baselines_config.md
 
 @relatedsample:
-04_customization/15_baselines.html
+04_customization/15_baselines.html
+
+@changelog: added in v9.0

data/api/gantt_gettaskbaselines.md

@@ -2,7 +2,7 @@ getTaskBaselines
 =============
 
 
-@short: returns the array of baselines of a specific task from the datastore
+@short: returns an array of baselines of a specific task from the datastore
 
 
 @params:
@@ -20,7 +20,7 @@ gantt.getTaskBaselines(5); // -> see details
 @descr:
 {{pronote This functionality is available in the PRO edition only.}}
 
-{{note The **getTaskBaselines** method is not available if api/gantt_baselines_config.md is disabled.}}
+{{note The **getTaskBaselines** method is not available if the api/gantt_baselines_config.md config is disabled.}}
 
 The method returns an array with objects as in:
 
@@ -43,11 +43,10 @@ The method returns an array with objects as in:
 ]
 ~~~
 
+ 
 
-@relatedapi: 
 
-
-@related: desktop/resource_baselines.md
+@related: desktop/inbuilt_baselines.md
 
 @relatedsample: 04_customization/15_baselines.html
 

data/api/gantt_onbeforeselect_event.md

@@ -16,7 +16,6 @@ Gantt API
 - api/gantt_addtask.md - adds a new task
 - api/gantt_addtasklayer.md - displays an additional layer with custom elements for a task in the timeline area
 - api/gantt_adjusttaskheightforbaselines.md - adjusts the task's row height for proper display of baseline elements
-- api/gantt_adjusttaskheightforbaselines.md - adjusts the task's row height for proper display of baseline elements
 - api/gantt_alert.md - calls an alert message box
 - api/gantt_assert.md - if the specified expression is false, an errorMessage is shown in the red popup at the top right corner of the screen
 - api/gantt_attachevent.md - attaches the handler to an inner event of dhtmlxGantt
@@ -115,7 +114,7 @@ Gantt API
 - api/gantt_gettask.md - returns the task object
 - api/gantt_gettaskassignments.md - returns the parsed resource assignments of a specific task from the datastore
 - api/gantt_gettaskbarheight.md - returns the height (in pixels) of the DOM element of the task
-- api/gantt_gettaskbaselines.md - returns the array of baselines of a specific task from the datastore
+- api/gantt_gettaskbaselines.md - returns an array of baselines of a specific task from the datastore
 - api/gantt_gettaskby.md - finds a task by the specified criteria
 - api/gantt_gettaskbyindex.md - returns a task by its global task index
 - api/gantt_gettaskbytime.md - returns a collection of tasks which occur during the specified period

data/api/refs/gantt.md

@@ -110,7 +110,7 @@ Methods
 - api/gantt_gettask.md - returns the task object
 - api/gantt_gettaskassignments.md - returns the parsed resource assignments of a specific task from the datastore
 - api/gantt_gettaskbarheight.md - returns the height (in pixels) of the DOM element of the task
-- api/gantt_gettaskbaselines.md - returns the array of baselines of a specific task from the datastore
+- api/gantt_gettaskbaselines.md - returns an array of baselines of a specific task from the datastore
 - api/gantt_gettaskby.md - finds a task by the specified criteria
 - api/gantt_gettaskbyindex.md - returns a task by its global task index
 - api/gantt_gettaskbytime.md - returns a collection of tasks which occur during the specified period

data/api/refs/gantt_methods.md

@@ -238,6 +238,11 @@ After that you can customize the display of deadlines by [creating a custom dead
 The **gantt.config.deadlines** config enables or disables the display of deadline elements for tasks. If enabled, Gantt will check the **task.deadline** property, 
 and if it contains a valid date, the deadline element will be displayed in the timeline.
 
+### Task constraints
 
+When [auto scheduling](desktop/auto_scheduling.md) is enabled and works in the Constraint mode (api/gantt_auto_scheduling_compatibility_config.md is set to *false*),
+Gantt will automatically display constraint dates in the chart. 
+
+{{sample 02_extensions/19_constraints_scheduling.html}}