[Lens] [Docs] Add more QA for Lens

docs/user/dashboard/lens.asciidoc

@@ -179,6 +179,8 @@ A subset of *Lens* visualizations support value labels.
 [role="screenshot"]
 image::images/lens_value_labels_xychart_toggle.png[Lens Bar chart value labels menu]
 
+NOTE: In bar charts, you are unable to move the label positions.
+
 * *Pie*, *Donut*, and *Treemap*
 +
 [role="screenshot"]
@@ -232,6 +234,9 @@ refer to <<explore-fields-in-your-data,Explore the fields in your data>>.
 
 Sorting dimensions in visualizations is unsupported in *Lens*.
 
+You can sort the dimensions for a single column in data tables: click the column header, then select the sorting criteria you want to use.
+If you use the dimension as `Columns`, then all the columns that belong to the same dimension are sorted in the table.
+
 [float]
 [[is-it-possible-to-use-saved-serches-in-lens]]
 ===== How do I visualize saved searches?
@@ -243,3 +248,47 @@ Visualizing saved searches in unsupported in *Lens*.
 ===== How do I change the number of suggestions?
 
 Configuring the *Suggestions* that *Lens* automatically populates is unsupported.
+
+[float]
+[[is-it-possible-to-use-different-indexpatterns-in-lens]]
+===== Can I visualize multiple index patterns in a single visualization?
+
+You can create *Bar*, *Line* and *Area* charts from multiple index patterns.
+
+Each *Layer* in a visualization is associated with an index pattern and mutiple *Layers* can be combined together within the same visualization. Each *Layer* also has a chart switcher button in order to select the best type of visualization for the specific dataset.
+You can also change the index pattern for a single *Layer*.
+
+[float]
+[[why-my-field-x-is-missing-from-the-fields-list]]
+===== Why is my field X missing from the fields list?
+
+*Lens* does not support the visualization of full-text fields, therefore it is not showing them in the data summary.
+
+[float]
+[[how-to-handle-gaps-in-time-series-visualizations]]
+===== How do I handle gaps in time series visualizations?
+
+*Lens* provides a set of features to handle missing values for *Area* and *Line* charts, which is useful for sparse data in time series data.
+
+To select a different way to represent missing values, open the *Visual options* menu, then select how to handle missing values. The default is to hide the missing values.
++
+[role="screenshot"]
+image::images/lens_missing_values_strategy.png[Lens Missing values strategies menu]
+
+[float]
+[[is-it-possible-to-change-the-scale-of-Y-axis]]
+===== Is it possible to statically define the scale of the y-axis in a visualization?
+
+The ability to start the y-axis from another value than 0, or use a logarithmic scale, is unsupported in *Lens*.
+
+[float]
+[[is-it-possible-to-have-pagination-for-datatable]]
+===== Is it possible to have pagination in a data table?
+
+Pagination in a data table is unsupported in *Lens*. However, the <<types-of-visualizations,aggregation-based data table>> supports pagination.
+
+[float]
+[[is-it-possible-to-have-more-than-one-Y-axis-scale]]
+===== Is it possible to have more than one y-axis scale in visualizations?
+
+*Lens* lets you pick, for each Y dimension, up to two distinct axis: *left* and *right*. Each axis can have a different scale.