Select material to Place or Edit - Thumbnails and preview, Add In-Model problems

I’m a newbie who did some interior design in SketchUp during the apartment renovation and decided to render it. Some ones have recommended me to use v-ray for rendering, but I think v-ray not very friendly and, by the same, when I ask them how to clip the walls, they shrugged.

Find iRender by accident I was impressed of speed, quality and of cause multi-multi-functionality. Decided to learn it more deeply and began to find some problems and questions that I'm going to ask here in the next several posts.

First of them was with window “Select material to Place or Edit”. Try to explain below (by the way, my apologies for the language mistakes).

I. Thumbnails and preview problems with Library’s materials:

- I’ve opened the dialog “Select material to Place or Edit” and chosen the material “car paint blue metallic” (or anyone else), clicked the “Place” button and applied it to several faces.

- Than changed the library and returned to “Car Paints” folder again. And found that thumbnails and preview of my last placed material looks like skin. :( And it doesn’t appear after restart even!

- At the same time into the Windows browser its thumbnail and characteristics are still correct.

II. Add materials In-Model problem:

- I’ve diced to add the material in model before applying it and faced with another problem.

Opened the dialog “Select material to Place or Edit”, chosen the material “car paint red metallic” (Reflectivity 62%) and clicked the “Add “ button.

- Then, opened the In Model folder and found the material with two mistakes:

the characteristics have been applied from last edited material (in my case it was “car paint blue metallic” with Reflectivity 25%)
the additional texture has been added from thumbnails preview

- At the same time into the Windows browser its characteristics are still correct.