Unable to control custom symbol icon display in the mobile UI

[lpechacek]

Steps to reproduce

1. Create custom symbol icons for (some) symbols. Custom icons have been introduced in PR Custom icon support #1129.
2. Save the file as .omap file.
3. Open the file in the mobile Mapper version.

Actual behaviour

In some cases, only the generated icons show up. There is no control over which icons will be displayed. (The desktop version features the "Show custom icons" checkbox in the symbol context menu.)

Expected behaviour

There should be some way to choose between the generated and custom icons in the mobile version.

Configuration

Mapper Version: 0.9.5
Operating System: Android